I've came across this bug and have not been able to find a solution as of yet. Maybe someone who understands how the database maps versions would have some insight to this. As the only way I've ever fixed this is reverting the database backward.

If your file permissions have changed, and the web server user can no longer write files (say during a hosting transfer), but you go into the site and make changes to a page, you will get an error and have to go fix your permissions. But what happens is you start getting a "Compare Versions" notice on the page, and it will never go away, no matter what you do you can never get i to go away. Can someone help with this? I saw one other post of someone with same issue a while back and I'm not the outcome. Heres a screenshot of what will not go away if you've accidently tried to make edits with file permissions on the server wrong.