TOPIC: Final Cut Backups delayed...

I'm sure this is a dumb question. I went into a project folder in Movies, Final Cut Backups today for the first time in several days. Had procrastinated duplicating the current backup to put on our server. For some reason with minor editing in the timeline and some additional clips imported, Final Cut has not done any auto backups in a couple of days (specifically referring to the "Final Cut Backup" folder). Decided to go ahead and update to 10.5. After a few more minor edits and FCP sitting open over lunch, still no backups. Just recently, after doing more involved editing in the timeline, several backups have been auto generated with the usual date and time stamp. Is this a bug, feature or just my user error? Can't seem to find anything in this forum or elsewhere online.