A catastrophic error that has occurred in previous versions of InDesign has come back with the latest 2021 release. Now, at a random moment when you hit cmd-z to undo, InDesign will instead revert back to the last saved version of the document. Just lost an hour of work.
I've been using InDesign 2021 a lot the past few weeks (I tested it in prerelease and wrote an article on it for CreativePro.com) and haven't encountered or heard that problem. To be fixed by the engineers, it has to be reproducable. Has this only happened one time with one file? (It's possible there could be corruption in the file.) Can anyone else confirm it's happened to them?
Sorry to hear about your experience. Would you mind sharing the version of the OS? Also, as Steve asked earlier, does it happen with a specific file or all? Is this files saved on a network drive or local?
This information would help us understand the concern and assist you accordingly. Looking forward to your response.