Hi Kai,
I believe that both nodes were rebuilt a week back with RC1 and there has not been a reoccurrence of this fault so far. However, I've not been in the office recently and therefore I'm guessing the servers are not getting that much of a workout [:D] Will test again in +1 week when I'm back from hols.
https://community.sophos.com/products/unified-threat-management/astaroorg/f/102/t/69686
Cheers,
Darren
