Just had something strange happen:

I logged in, opened to the Selling tab and noticed after a while that all my favorites were gone. Reopening AH several times didn't change anything.

I duplicated the SV files and reloaded the UI. All favorites were back now (from the active SV file, not from the backup).

Also weird: In the session where the favs were absent, I added an item to the favs (before I noticed it). After the reload, that item was twice in the favs, presumably one from before and one from the recent adding.

This was with Auctionator 10.2.31-2-g05cb291 on Retail. No errors logged in BugSack.