I Had the same Problem, but I think I have a possible solution. We have two ASG 220 @work doing a good job. But then the mail ... 86% fill up. Ok I restartet, no. No resulution, then checked all folders, found nothing.
But when doing the manual Pattern update via the update Button System -> Up2date Service -> Latest Pattern Up2Dates [update] Lines (Astaro Virus Protection / Open source Virus Protection ) next to view.
After this I had had 78% fillup.
only works with manual update for both Patterns, tried it with Do Pattern Update -> Start. Nothing.