Homeworld 2 Complex mod

I used the artillery frigates in at least 5 games since the 8.4.3 release and haven't seen this.
What was your target? What map/gametype, game year etc?

Oh goody you're on while i write this ^.^

Jupiter fields map, i was aiming three stolen frigates at stationary scouts, i got annoyed that i can't take out enemy scouts without 12 of my own scouts, they just sit there out of range of my mothership, and fly away when they get shot at, unless it's from a long range frigate or something else.
Anyway even when they faced the scouts i had to keep moving them a tiny bit to make them face the scouts dead center otherwise they would just sit there trying to encounter them but not shooting because they weren't facing them down the red target line.

Oh gametype? not sure, just set the AI to defensive, but AI scouts always just sit there out of range not moving until something comes close to them before they fly away, but they just come back if you leave them alone.

Scouts aren't exactly the target meant for an artillery frigate. It's even possible that we didn't add an attack style to the files, because... well we're talking about trinity cannons here, the most powerful weapon in vanilla homeworld 2 other than phased ion cannons.
These are solely anti frigate/capital ship weapons, so that's what you should use them for.

Yes i did read the description about them being anti frigate/capital, but stealing 3 of them and moving them to face the scouts just right, 1 hit per unit and the scouts are down. AI don't need to do that with scouts, they send plenty of probes to bug my perimeter, they already know where i am before they send scouts or probes.
The rest of the AI fleet (frigates, capital ships, motherships) pretend to move as if they don't know where my mothership is, but of course they are only sending ships to secure resource points. Once all the resources on the map are up, where do they send carriers and motherships? they send them one by one to me, on a suicide mission, on defensive. A defensive AI sending a mothership by itself, leaving the protective area of it's gun platforms it placed earlier in the game, coming at my 17 frigates, 4 capital ships, 2 combat stations, a horde of scouts, and my mothership and shipyard (i don't use corvettes since salvage corvettes are no longer an option)