GW2 split-screen crashing

In PVZ: GW2 playing team vanquish in split screen, I get random crashing. Sometimes everything freezes in the game, but not the Xbox. Other times it is a frame rate/stuttering issue where you get one frame every 2-3 seconds. This has only happened to me in split screen and appears to be random. Sometimes it happens within 5 minutes, other times I can play for an hour straight with no problem. Suggestions?