I was going through a comp stomp and dropped an Arcane monolith to make life more difficult for a Magnar Pioneer that was searching for a place to make a city. Monsters were roaming everywhere, so I figured there was a good chance it would get gobbled up. While it skirted its way around my new territory, lo and behold a Ravenous Harridan's army (packing itself, two brood hunters, and two black widows) seemed to pounce on it. Oddly enough, they've apparently decided to play nice together and they just show up as stacked armies: one with the completely healthy pioneer and the other the completely intact army of the Ravenous Harridan.
Is this intentional behavior to perhaps give the AI a more sporting chance, or is this a bug like it appears to be?