I just finished redoing my edits lost yesterday. Interestingly, at the end I was going to quit FCP to force a save, but it warned me there were tasks in progress… Transcoding and Analysis (6%), Rendering (0%) and Backup (0%). So I went to check the backup directory, and while there were a few backups 15 minutes apart, there were none for the previous 45 minutes of editing. So I paused the first two… Still no progress on the backup. I killed Transcoding and Analysis, and there was a blip in Backup, and magically the latest backup appeared.
This seems like some sort of a defect, but I don’t know definitively if it’s the T&A that’s blocking the backup.