I have not experienced anything like that, nor has anybody else reported anything like that. Did the sheet get trashed immediately after you did some type of action, or did you just login again and notice the sheet was in the trash?
Does anybody else have access to the system that could have maybe trashed something by accident?
There is a setting to automatically purge expired sign-ups, but that shouldn’t happen on ongoing sheets. Perhaps your system’s date/time settings are different in some way and it thinks they are expired. Maybe turn off the automatic deleting of expired sign-ups to see if that changes anything??
You may also want to try deactivating the plugin and then reactivating it, which will run the dbDelta function again to make sure the database tables it uses are updated to the newest version. A couple of updates ago I introduced a new field on the sheets that required a new database column. If, for some reason, the database table didn’t get updated correctly on your system, that could cause some unpredictable behavior (although I would suspect it would just throw a fatal error instead).
At this point, I’m just guessing as this is not something I can recreate on my own system.