Wretched Defiler Spectres: The corpses they spawn are literally breaking the game

This is the mess after doing the feared, the corpses lag my game and can make models spawn in reference pose (I saw a shaper clone A pose at me and it was horrifying).

My prefered idea would be the monsters they spawn don't leave a corpse, because having the rhoa charge at and stun Sirus out of his rotating beam is very funny, but if that can't be done please disable it on the spectre so I can see whats going on, it makes doing any prolonged fight borderline impossible.