I am 99% sure that Lizzie is the one that makes the horde matches crash after TU4
I made several posts about it on different threads and my own. It’s Lizzie for sure. It happens at the end of the ultimate, and in my experience fighting flyers. It also happens in escape against certain Scion enemies. Competing salvos for example. It may be as simple as switching her weapon loadout, but that’s just a guess.