The error is "too many heap sections" (iirc) and it means the managed heap isn't allowed to get more memory so the game just dies, Is this just in MP or SP too?
In the past I've figured this was just because it was totally running out, but I'm starting to wonder if maybe it's that there's enough heap available but it gets really fragmented due to lots of allocation and deallocation and allocation and deallocation, etc.