The Aegis Flak Autocannons are firing very rarely on my buddy's multiplayer world, only firing in short bursts when they do and usually not firing at all, even when they have a clear line of sight and are well within range, and fully loaded.

It's so bad that I thought they only fired in bursts of four shots at a time until I did testing in single player. Any idea what might be causing this?

All the 40K weapons have their moments in multiplayer, like refusing to recognize targets or failing to fire on their own, but when I slap 40 Aegis Flak turrets on a destroyer, I expect them to work at least most of the time.