Twenty Fifteen Broken After Update?

Hi @johnfriscia0,

You mentioned this error is occuring in the AMP version of your page – is that the only place? If you disable your AMP plugin do you still see the issue occuring?

Hello, thank you for the reply. I use Twenty Fifteen theme exclusively for the AMP theme; I otherwise use the quaint Ten Blog theme for desktop/non-mobile. There are no display problems with the Ten Blog theme, both on desktop and on my phone.

Hi @johnfriscia0,

I’m a little unclear on what you mean. My expectation is that AMP is enabled by a plugin, rather than part of the theme itself. Do you have an AMP plugin installed?

Hi @jordesign. Yes, I have the AMP plugin installed. If people come to my website from a mobile device, they get automatically directed to the AMP version of the website, which uses Twenty Fifteen theme (except on the home page). If you visit the website from desktop or “exit the mobile site” on mobile, you get the Ten Blog theme.

But on that note, I am noticing something I hadn’t noticed before. I’m not sure if it’s the culprit or just a temporary quirk, but in “AMP Settings” in WordPress, under “Site Scan,” I am seeing it claim Twenty Fifteen is a theme with “AMP incompatibility” due to a long string I can’t make heads or tails of, below. The article URL referenced at the top is an article published late last night/early this morning.

[
{
"url": "https://kpopanswers.com/how-old-are-the-xodiac-members/",
"type": "is_singular[post]",
"label": "Post",
"amp_url": "https://kpopanswers.com/how-old-are-the-xodiac-members/?amp=1",
"validation_errors": [
{
"code": "STYLESHEET_FETCH_ERROR",
"type": "css_error",
"url": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=6.4.1",
"message": "Failed to fetch: https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=6.4.1 (HTTP 404: Not Found)",
"node_name": "link",
"parent_name": "head",
"node_attributes": {
"rel": "stylesheet",
"id": "ten-blog-blocks-css",
"href": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=normalized",
"type": "text/css",
"media": "all"
},
"node_type": 1,
"sources": [
{
"type": "theme",
"name": "twentyfifteen",
"file": "functions.php",
"line": 257,
"function": "ten_blog_scripts",
"hook": "wp_enqueue_scripts",
"priority": 10,
"dependency_type": "style",
"handle": "ten-blog-blocks"
}
]
},
{
"node_name": "script",
"parent_name": "head",
"code": "DISALLOWED_TAG",
"type": "js_error",
"node_attributes": {
"type": "text/javascript",
"src": "https://kpopanswers.com/wp-includes/js/jquery/jquery.min.js?ver=normalized",
"id": "jquery-core-js"
},
"node_type": 1,
"sources": [
{
"type": "theme",
"name": "twentyfifteen",
"file": "functions.php",
"line": 257,
"function": "ten_blog_scripts",
"hook": "wp_enqueue_scripts",
"priority": 10,
"dependency_type": "script",
"handle": "ten-blog-custom-script",
"dependency_handle": "jquery-core"
},
{
"type": "theme",
"name": "twentyfifteen",
"file": "functions.php",
"line": 257,
"function": "ten_blog_scripts",
"hook": "wp_enqueue_scripts",
"priority": 10,
"dependency_type": "script",
"handle": "ten-blog-navigation",
"dependency_handle": "jquery-core"
}
]
},
{
"node_name": "script",
"parent_name": "head",
"code": "DISALLOWED_TAG",
"type": "js_error",
"node_attributes": {
"type": "text/javascript",
"src": "https://kpopanswers.com/wp-includes/js/jquery/jquery-migrate.min.js?ver=normalized",
"id": "jquery-migrate-js"
},
"node_type": 1,
"sources": [
{
"type": "theme",
"name": "twentyfifteen",
"file": "functions.php",
"line": 257,
"function": "ten_blog_scripts",
"hook": "wp_enqueue_scripts",
"priority": 10,
"dependency_type": "script",
"handle": "ten-blog-custom-script",
"dependency_handle": "jquery-migrate"
},
{
"type": "theme",
"name": "twentyfifteen",
"file": "functions.php",
"line": 257,
"function": "ten_blog_scripts",
"hook": "wp_enqueue_scripts",
"priority": 10,
"dependency_type": "script",
"handle": "ten-blog-navigation",
"dependency_handle": "jquery-migrate"
}
]
},
{
"node_name": "script",
"parent_name": "body",
"code": "DISALLOWED_TAG",
"type": "js_error",
"node_attributes": {
"type": "text/javascript",
"src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/skip-link-focus-fix.js?ver=normalized",
"id": "ten-blog-skip-link-focus-fix-js"
},
"node_type": 1,
"sources": [
{
"type": "theme",
"name": "twentyfifteen",
"file": "functions.php",
"line": 257,
"function": "ten_blog_scripts",
"hook": "wp_enqueue_scripts",
"priority": 10,
"dependency_type": "script",
"handle": "ten-blog-skip-link-focus-fix"
}
]
},
{
"node_name": "script",
"parent_name": "body",
"code": "DISALLOWED_TAG",
"type": "js_error",
"node_attributes": {
"type": "text/javascript",
"id": "ten-blog-navigation-js-extra"
},
"text": "\n/* /\nvar ten_blog_l10n = {DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING};\n/ ]]> /\n", "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "extra_key": "data", "text": "var ten_blog_l10n = {\"quote\":\" <\/use> <\/svg>\",\"expand\":\"Expand child menu\",\"collapse\":\"Collapse child menu\",\"icon\":\" <\/use> <\/span><\/svg>\"};", "handle": "ten-blog-navigation" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/navigation.js?ver=normalized", "id": "ten-blog-navigation-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-navigation" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/custom.js?ver=normalized", "id": "ten-blog-custom-script-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-custom-script" } ] } ], "stale": false }, { "url": "https://kpopanswers.com/about-us/", "type": "is_singular[page]", "label": "Page", "amp_url": "https://kpopanswers.com/about-us/?amp=1", "validation_errors": [ { "code": "STYLESHEET_FETCH_ERROR", "type": "css_error", "url": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=6.4.1", "message": "Failed to fetch: https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=6.4.1 (HTTP 404: Not Found)", "node_name": "link", "parent_name": "head", "node_attributes": { "rel": "stylesheet", "id": "ten-blog-blocks-css", "href": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=normalized", "type": "text/css", "media": "all" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "style", "handle": "ten-blog-blocks" } ] }, { "node_name": "script", "parent_name": "head", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-includes/js/jquery/jquery.min.js?ver=normalized", "id": "jquery-core-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-custom-script", "dependency_handle": "jquery-core" }, { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-navigation", "dependency_handle": "jquery-core" } ] }, { "node_name": "script", "parent_name": "head", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-includes/js/jquery/jquery-migrate.min.js?ver=normalized", "id": "jquery-migrate-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-custom-script", "dependency_handle": "jquery-migrate" }, { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-navigation", "dependency_handle": "jquery-migrate" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/skip-link-focus-fix.js?ver=normalized", "id": "ten-blog-skip-link-focus-fix-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-skip-link-focus-fix" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "id": "ten-blog-navigation-js-extra" }, "text": "\n/ /\nvar ten_blog_l10n = {DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING};\n/ ]]> /\n", "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "extra_key": "data", "text": "var ten_blog_l10n = {\"quote\":\" <\/use> <\/svg>\",\"expand\":\"Expand child menu\",\"collapse\":\"Collapse child menu\",\"icon\":\" <\/use> <\/span><\/svg>\"};", "handle": "ten-blog-navigation" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/navigation.js?ver=normalized", "id": "ten-blog-navigation-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-navigation" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/custom.js?ver=normalized", "id": "ten-blog-custom-script-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-custom-script" } ] } ], "stale": false }, { "url": "https://kpopanswers.com/?s=example", "type": "is_search", "label": "Search Results", "amp_url": "https://kpopanswers.com/?s=example&=1", "validation_errors": [ { "code": "STYLESHEET_FETCH_ERROR", "type": "css_error", "url": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=6.4.1", "message": "Failed to fetch: https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=6.4.1 (HTTP 404: Not Found)", "node_name": "link", "parent_name": "head", "node_attributes": { "rel": "stylesheet", "id": "ten-blog-blocks-css", "href": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/css/blocks.css?ver=normalized", "type": "text/css", "media": "all" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "style", "handle": "ten-blog-blocks" } ] }, { "node_name": "script", "parent_name": "head", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-includes/js/jquery/jquery.min.js?ver=normalized", "id": "jquery-core-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-custom-script", "dependency_handle": "jquery-core" }, { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-navigation", "dependency_handle": "jquery-core" } ] }, { "node_name": "script", "parent_name": "head", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-includes/js/jquery/jquery-migrate.min.js?ver=normalized", "id": "jquery-migrate-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-custom-script", "dependency_handle": "jquery-migrate" }, { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-navigation", "dependency_handle": "jquery-migrate" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/skip-link-focus-fix.js?ver=normalized", "id": "ten-blog-skip-link-focus-fix-js" }, "node_type": 1, "sources": [ { "type": "theme", "name": "twentyfifteen", "file": "functions.php", "line": 257, "function": "ten_blog_scripts", "hook": "wp_enqueue_scripts", "priority": 10, "dependency_type": "script", "handle": "ten-blog-skip-link-focus-fix" } ] }, { "node_name": "script", "parent_name": "body", "code": "DISALLOWED_TAG", "type": "js_error", "node_attributes": { "type": "text/javascript", "id": "ten-blog-navigation-js-extra" }, "text": "\n/ /\nvar ten_blog_l10n = {DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING,DOUBLE_QUOTED_STRING:DOUBLE_QUOTED_STRING};\n/ ]]> */\n",
"node_type": 1,
"sources": [
{
"type": "theme",
"name": "twentyfifteen",
"file": "functions.php",
"line": 257,
"function": "ten_blog_scripts",
"hook": "wp_enqueue_scripts",
"priority": 10,
"dependency_type": "script",
"extra_key": "data",
"text": "var ten_blog_l10n = {\"quote\":\" <\/use> <\/svg>\",\"expand\":\"Expand child menu\",\"collapse\":\"Collapse child menu\",\"icon\":\" <\/use> <\/span><\/svg>\"};",

"handle": "ten-blog-navigation"

}

]

},

{

"node_name": "script",

"parent_name": "body",

"code": "DISALLOWED_TAG",

"type": "js_error",

"node_attributes": {

"type": "text/javascript",

"src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/navigation.js?ver=normalized",

"id": "ten-blog-navigation-js"

},

"node_type": 1,

"sources": [

{

"type": "theme",

"name": "twentyfifteen",

"file": "functions.php",

"line": 257,

"function": "ten_blog_scripts",

"hook": "wp_enqueue_scripts",

"priority": 10,

"dependency_type": "script",

"handle": "ten-blog-navigation"

}

]

},

{

"node_name": "script",

"parent_name": "body",

"code": "DISALLOWED_TAG",

"type": "js_error",

"node_attributes": {

"type": "text/javascript",

"src": "https://kpopanswers.com/wp-content/themes/twentyfifteen/assets/js/custom.js?ver=normalized",

"id": "ten-blog-custom-script-js"

},

"node_type": 1,

"sources": [

{

"type": "theme",

"name": "twentyfifteen",

"file": "functions.php",

"line": 257,

"function": "ten_blog_scripts",

"hook": "wp_enqueue_scripts",

"priority": 10,

"dependency_type": "script",

"handle": "ten-blog-custom-script"

}

]

}

],

"stale": false

}

]

@jordesign Regarding the text above that I copy/pasted, the error regarding that recent article has indeed disappeared. The error mostly only remains present for my About Us page and, bizarrely, ” https://kpopanswers.com/?s=example ,” the latter of which sounds like a non-issue to me. Unfortunately, I am not any closer to solving my problem though.

Hey @johnfriscia0 – interestingly I don’t see those issues/errors when checking those pages (either the AMP or non-AMP versions). Do you still get the errors if you are logged out?

One other thing that would be helpful to try – could you try temporarily activating Twenty Fifteen for the whole site and see if the display issue still occurs?

Hi @jordesign. While I did not fully activate Twenty Fifteen across the whole website, I did “preview” what it would look like if I activated the theme (through WordPress, and outside of the AMP plugin), and it looks just as broken as Twenty Fifteen currently does as my AMP layout. Additionally, for a point of comparison, I installed Twenty Sixteen theme and previewed that, and it too looks similarly broken (if not even worse).

However, I did just notice a curious detail that I hadn’t before: When I look at the site in Twenty Fifteen theme in any form, including on my phone (or when I preview Twenty Sixteen on desktop), the bottom retains this text, “Theme Ten Blog by Kantipur Themes,” as if it’s trying and failing to serve my Ten Blog theme *inside* of those other themes. In fact, I installed a random extra theme, “Go” by Go Daddy, and I still see that text in preview, along with an extremely broken layout.

With or without AMP, it seems something is highly broken in my ability to use any WordPress theme *other* than my default Ten Blog theme at the moment. So, this is potentially a more serious issue than I’d originally thought. I genuinely can’t recall doing anything recently with my website structurally other than updating to the most current WP version; I did a reinstall to see if that would fix anything, but it didn’t. Besides that, it looks like all I’ve done recently is update the Hostinger plugin. I deactivated that plugin for a moment to see if it would do anything, and I don’t think it did.

So, I’m really at a loss at what to do here… Any advice would be extremely appreciated. Thank you so much.

Hi @johnfriscia0 – that definitely sounds very odd that it’s effecting all those themes.

One thing to double check – have you tried seeing how the display works for those themes (or at least TwentyFifteen) with all plugins disabled?

Hi @jordesign, really appreciate your efforts to help. I have not tried disabling *all* plugins at once, as that could cause some real grief to my website. (I wish I had the know-how to create a backup test site… I’ll have to learn someday.) I have tried disabling all the non-crucial plugins individually with no results though.

I’m starting to think this is genuinely a bug I experienced as a result of updating to WordPress 6.4.1, because it remains the only notable thing I’ve done in the past week. I’m wondering if I should wait/hope for a 6.4.2 (etc.) or attempt to revert to a previous version… but I also don’t have much know-how in how to revert an update either!

Oh @jordesign, there is one more clue I’d neglected to mention! This entire time, I notice I have been unable to live-preview the new Twenty Twenty-Four theme with my website, even after an uninstall and re-install. In fact, I can’t live-preview *any* theme if it’s in a screen using this format, with the editing style on the left: https://i.imgur.com/fUFaxtS.jpg I just end up getting that blank screen that never loads anything.

I can only live-preview a theme if it appears with this format, with the traditional WordPress customization layout: https://i.imgur.com/aYyqJPW.jpg (seen here with Twenty Sixteen and looking awful)

I don’t actually know or understand at the moment (besides maybe age of theme?) why I get the unusable live-preview format sometimes and the old format elsewhere. So, that’s another oddity I’m experiencing! Thank you!

Hi @johnfriscia0 – it definitely does sound like there’s some oddity going on – something that is affecting the way the styles are loading in your site.

I’m starting to think this is genuinely a bug I experienced as a result of updating to WordPress 6.4.1, because it remains the only notable thing I’ve done in the past week. I’m wondering if I should wait/hope for a 6.4.2 (etc.) or attempt to revert to a previous version… but I also don’t have much know-how in how to revert an update either!

One way to check this *would* be to roll back to WordPress 6.4.0 and see if that makes a difference. Is that something you’d be willing to try?

Hello @jordesign. I ultimately used the “WP Downgrade” plugin to revert back to WP *6.3.8*, which it turns out *does* fix my Twenty Fifteen layout! On desktop and mobile both. So, I am very glad my website looks right again–but now I’m equally worried for my website’s long-term security if another WP update doesn’t address my unusual issue. Is there anything further you would suggest or anyone you would recommend I try to file a “report” with, etc.?

Thank you so much.

(Also, just as another little FYI, I didn’t realize that 6.4.1 was released only two days after 6.4. I had waited a bit before installing the update in the first place, so it’s *possible* I had never had 6.4 installed. I may have gone from 6.3.8 straight to 6.4.1, but I’m having a difficult time locating documentation in my installation to prove it.)

Hi @johnfriscia0 – I’m glad to hear that rolling back resolved the issue for now. And I can totally understand the desire to still figure out a solution for updating in the future…

It’s definitely odd that it seems to have started happening as a part of the upgrade to WP 6.4 (or 6.4.1). I’ve been testing those older bundled themes (TwentyFifteen, TwentySixteen etc) and have been unable to recreate the issue so far. Which does lead me to think it is an issue specific to your site.

That being the case – the best I can offer is some suggestions of other things to try out if/when you upgrade to see if it helps.

1. I forgot to check if you have installed the Gutenberg plugin to see if it makes a difference? If not – i’d recommend trying that out.
2. Given that the issue seemed to be with stylesheets not loading correctly – I’d suggest double checking the permissions of your files on your hosting/server to make sure they are accessible.

Hi @jordesign. I wanted to thank you one more time for all of your assistance, and I also wanted to inform you that the new WP 6.4.2 December update seems to have remedied my site issues! The new version of Site Customize loads for me now, and my website isn’t broken on mobile with the latest update. (Granted, I’ve only had the update active for 30+ minutes, but so far, so good!) So, it seems all’s well that ends well, even though I was basically just at WordPress’s mercy the whole time!

Happy holidays to you!