I believe GOG Galaxy may have just caused me to lose hours of progress in The Witcher 3 and am looking for clarification on why. I last played the game 3 days ago, and I remember when I quit, GOG Galaxy said it was having trouble syncing my save to the servers. I didn't think much of it because I only play on one computer, so I have local copies of the save files that I can use. However, when I played today, I found that all of my saves were from that day, but they were from earlier than when I quit playing. My best guess is that GOG Galaxy backed up my saves at an earlier point that day (maybe I took a break and then played again later? I don't remember) but not after the last time I saved, and then when I played today, it overwrote my newer local saves with older cloud saves. Is this supposed to happen? I thought it would've compared the timestamps on the local and cloud saves to see which was newer.

Shouldn't work that way. Should use the save which is most recent... but they did push Galaxy 2.0 on us while it was still in beta instead of letting us keep using the original.

I assume you've turned off any cloud saving options in both Galaxy and the game itself?

No, I have not, but I'm thinking about it. And I guess it's technically possible the game failed to save locally but it just seems unlikely since I'd played like 50 hours at that point and didn't have any issues with saving, whereas this time all of my saves were outdated.

Same problem here with Gothic 3. GOG had problem with sync and I played without it for couple of days. Fortunately only quick save is lost.