I’m having the same issues across all of my sites. No code was updated or changed - it just all of a sudden started happening for live code. From the pages I’m seeing issues with it especially seems to be connected to databases? Like dynamic pages have issues, but some of my non-dynamic ones don’t. Very odd…
When this issue has happened to me previously, I was usually able to revert to an older version of the site and it would resolve, but that hasn’t been the case this time.
