Anything with a custom field won’t update anymore

After using this plugin successfully for years, my WordPress site seems to be having problems with (huge) custom fields, and I was wondering if anyone else has experienced the same issue..

I’ve been using the Code Embed plugin to insert ~20 very large (average 3000-5000 lines of code each) chunks of (mixed javascript and html) code into various WordPress pages, and for years this has worked fine.

But suddenly, any page with a custom field cannot be updated (I get no errors, even in debugging mode, and just get dropped back to the main page), and menus can’t be updated. This does not *appear* to be an issue of the max_input_vars PHP setting being too small (I’ve deleted all menus, and still can’t make any changes).. I have the limit detector plugin installed, and am not getting any warnings.

Could the size of the custom fields I’m using with the Code Embed plugin potentially be a problem? Thanks!