AI won't attack neutrals

So, while testing my mod, I noticed that the AI will often times invade a planet, kill half the militia, then just stop the invasion. The ships will be right beside the neutrals and they won't attack. The neutrals will continue attacking though.

I ordered my ally to attack the neutral and he said "I will not attack my ally" what the heck!?

I also noticed that they will attack sporatically eventually killing the ship after a good 10 minutes.  

Anyone know what might be causing this? It usually only happens with one or two AI in a game.