Hidden Arcana (LS2,Pt5) domain of energy draining post-boss cinematic causing to get booted

[Ravien Coromana.4792]

So this isn't actually happening to me but rather my father (halfdragon.9163). For some reason, and we've repeated it three times now, both with and without him as the party leader, every time we finish the cinematic in the domain of energy draining on the mission, it boots him from the game, giving the generic "disconnected from the game server" message. Any idea why this would be happening or how to remedy it?