Yes, unfortunately. I think I have had that error message popping out perhaps four to five times so far in total.
I dont understand myself what causes it and it crashes the client every time, in matches often stealing your 'victory' which can be little annoying if you play pantheon.
What I can say about it, it seems to hold some last hundred lines of what exactly the client were attempting to run and in the end probably is the culprit of what made the client crash. It seems to be for debugging purposes a error logfile to help tracking down why the client crashes, as it shouldnt really.