Yeah, the server has been a bit unstable in peak times lately. We are currently moving the whole thing into a new datacenter which (as far as my understanding goes) should help combat these troubles.
As long as we are a free service (not that I would change that by any means) there will never be 100% guarantees - we can only pay for so much computing power - but it should get better 
It’s a lot of data though, so it takes time to transfer while staying operational. Will probably be at least several days or rather weeks more.
I will have to confer with my colleagues, but feel free to report those games, if they were in or close to endgame, with a safe advantage, I think we might consider annulling those at least to soften the error.
Sorry about the troubles.