"Preview Changes" and "View Change" display 2 different wrong pages

I cloned my site and imported it to a fresh WP Install and fresh theme install (Divi) with a new URL. I installed the WP Maintenance Mode plugin. Then I started to work on the pages. I created a new “home” page and a new “blog” page, initially giving them the URLs “home-test” and “blog-test”. When they were ready, I deleted the originals, emptied the trash, then designated the new “home” page as my static front page and the new “blog” page as my static posts page. I then renamed the URLS on the new ones to “home” and “blog.”

But now I have the following problem for the “blog” page:

I can view the page correctly in “Edit Page” mode.

But if I press “Preview Changes” it takes me to an older version of my Home page (not the current version of the “blog” page).

And if I press “View Page” it takes me to a different incorrect page, a ghost version of my “blog” page that was deleted (and trash emptied!).

If I simply click “Visit Site” and then click on the top menu link to “Blog” then it takes me to the ghost version as above.

If I designate the “contacts” page as the static posts page, then I can view the “blog” page normally, but the problem occurs to the “contacts” page instead (showing either a ghost version of the blog page, or an outdated version of the home page).

I have refreshed the permalinks as described in other support posts. I have logged out of WP and logged in again. I have cleared my browser cache. None of these things helped.

I deactivated the WP Maintenance Mode plugin and then deleted it, and then logged out of WP and back in again, but it has not helped.

Since this was a design test site, I don’t have any other plugins installed or running yet except WordPress Importer and Limit Login Attempts.

When I search for help in the forums I see people mentioning maintenance mode plugins sometimes in conjunction with this problem. I haven’t seen any threads about this issue that were definitely resolved with a solution that would be applicable to everyone. The WP MM plugin looks abandoned to me — hasn’t been updated in a year, and no support queries answered on their page.

I’ve seen some things in support forum threads that seem to suggest that a maintenance mode plugin could have created some lasting change that would not be reversed by simply deleting the plugin?

My site is at gaelic.co.

Thank you very much.