Server Performance in Infernal Hordes

I’ve been running T8 Hordes and I’ve noticed that depending on who I am playing with, the lag can go from normal, to abysmal, to unbearable, with my character rubberbanding around the room while my health bounces up and down.

Running cross-platform at the moment. Are there plans to address these sort of issues once party finder is implemented? Can we play locally? Would it matter?