Unfortunately, auto-backup was causing irrecoverable show corruption that would damage both your backups and your active show file. Auto-backup is supposed to help you recover from a damaged show, so having it cause damage was unacceptable.
For several versions in the 3.1.x series we strongly recommended leaving auto backup off, but it continued to cause problems for users. That is why we disabled it.
Fixing the corruption requires substantial changes to the database architecture, and is outside the scope of a patch release.
