What build of Axure RP 8 are you currently using? Is this the latest public build, 3355?
From your description, it sounds like the team projects that get corrupted are hosted on the same SVN server; does this server have vanilla configurations, with no hook scripts or anything similar running on it? Do you or your IT team know whether anything recently changed on the server at around the same time that this round of file corruption occurred? For example, was a scan run by any antivirus tools or other file scanners such as cleaning tools that might have modified files in the team repository? Do you encounter similar issues if you create a test team project on your desktop or on Axure Share?
It looks like you got an error message in Axure RP when the corruption happened; did this happen during a specific action, like editing a widget or saving a file? In order for us to take a look at the full error details, would you mind sending a copy of your Axure logs folder over to email@example.com? On Windows, that's located here:
If you send a zipped copy of the "logs" folder then we can take a closer look to see what Axure RP is reporting when the errors occur. Thanks!