Game Crashes whilst playing Multiplayer randomly during gameplay

Playing a Mercenary. Buddy is playing a Sorceress. Redoing Act 2 with him. Randomly crashing whilst playing through Keth/Bone Pits, seemingly no pattern other than perhaps attacking. Swapped to my Ranger and still crashing randomly.

Using controller on PC. Never had any crashes to desktop during gameplay at all. Map fog of war resets when this happens too, despite rejoining the same instance as my friend. I suspect it is something to do with multiplayer, maybe when I'm not the party leader.