Weird bug where ships fail to hold formation. The two hauler ships have a noticeably higher top speed than the fighter ship, and thus slow down to match it; however, due to how thruster utilization is incredibly bad, they for some reason power down one side of thrust only, and then try to balance it out with other thrusters; due to these ships not having strafe thrust, they just refuse to hold formation.
The underlying issue here is the really broken thruster utilization. I've always been a big proponent of fixing how the game uses thrusters to get a ship from point a to point b, since it seems like the system is very flawed and archaic. These ships control perfectly fine in manual control, too