Maybe it is related to Ai changing if they fought Bate, on old save i killed him after winning initiative roll while on new he started first and got hit by multiple drones before dying.
Could be related somehow. NPCs who use a shield have an internal timer that tells them when to turn it off if unused, and these guys' timers showed some strangely long intervals. I can't pinpoint what caused that, but I've added a few safety checks to the code and gave them some spare batteries so that they can recharge their shields if need be.