Dear Ryan,
thank you for looking into it all and sharing all this knowledge with me.
1) I will keep you updated if anything gets auto deleted again.
2) I double checked. The files are ".anim" -> Animation clips and ".controller" -> Animation Controller. I missread the files before and believed them to be the spritesheets.
The picture below shows the files that are always shown as "changed" when I open Unity. So I can check them in, close unity, open unity, and they are shown again.
3) Now that I understand the problem I can see how that must have happened. I had Unity freezing the other day several times when I tried to go back and forth the workspace in Plastic. It gave me a headache but I tried to solve problem one by going back and forth. I was testing things. Unity froze. I had to close it via task manager. Solved 😁👌 The other time our artist had that problem, I believe her Unity also froze and she closed it via Task Manager. I guess that is the problem, the root is that Plastic sometimes freezes Unity. I think the better way to use it is to use the Plastic App instead of using Plastic inside Unity. That way seems very stable, compaed to the Unity one which, well freezes sometimes.
Thank you a lot for taking your time, I think I understand Plastic a lot better and the problems we have with it.
Warm Regards,
Deniz