For me, it’s not causing a problem when I do the scheduled review for the day. It’s only happening when I complete that and then do a custom review selecting review forgotten cards. If I have any undo during the review of forgotten cards, then I get an error the next time I try to sync. This happens even if I just review today’s forgotten cards without a lookback to prior days. The check database function does not clear the error. Only a full sync seems to do the trick.