URGENT: Changes I made yesterday are gone today...and more

Did you find a fix for this? We are having a similar issue. We are version 8 of magazine revisions and some changes from version 3 and 4 are there, but others have reverted to earlier versions. The designer isn't saving to the Cloud—she's saving on her machine. 

InDesign is unlikely to be a cause here, directly or indirectly. It does no file management of its own accord.

First, are you on a network, using cloud storage or do you have any backup device (server, NAS, etc.)? One of those, either "being helpful" or misconfigured, would be my first suspect.

Otherwise, are you sure you are saving your new versions in the same place you're looking for them? Did you open old versions from an archive folder or the like, and perhaps save the new versions somewhere else, such as your system Documents folder?

Other than that, it has to come down to not saving the documents properly, or at all, despite what you think. It happens.

This might or might not have a happy, if face-palming solution. But in the future, get into a regular practice of saving while you work, and doing at least daily 'rolling backups' — save the file at the end of the day with an updated filename, and start with it the next day, and so forth. Keep 2-3 or more of these rolling versions on hand until you're done with the project or updates, then securely archive them.