I have a map where I fight some Klingons, and I'm escorted on either side by some Federation groups (patrol).
When we engage in combat, part way through both sides' NPCs will 'teleport' vertically almost 10km. No abilities being used that could push or jump them there, and everything is set at 0km height. They're just by my side one second, and the next they're several km above me.
Besides the patrol groups either side of me, all other NPC groups are set to legacy combat.