Rank reset and memory error

I get a memory error every 3-4 games in groundwar after last update…my pc is tip top, and Blizzard got no explanation. I asked for a refund since this is the gameplay i play 85% of the time. Blizzard says no, since playtime on acc is to high. Well ofc it is, i played a lot WHEN THE GAME WORKED!!!

And not sure if this is normal or not. Logged in last night to see update…wow, reset to rank 57 from rank 149.

Is that normal?