Can't create pull requests, they always result in a 500 error (BB-8048)

I can't make pull requests, i keep seeing a 500 error. I checked in Chrome Developer Tools and saw this on the 500 error page in the response, hopefully this helps identify the problem:

9380834b0ac34271a7a980e7173b75aa$902b284ba47444289b5eb9328c4c73f3