Insane Gauls

Hi.
I started a Romani campaign the other day and I conquered the northern homeland provinces in Italy exept for the one held by the Aedui. I had the follow AI option on (I know, I know, what was I thinking), and I noticed that every turn the garisson in the Aedui town would exit the city one space out and enter the same city over and over again until they ran out of movement points. Maybe its some secret barbarian training method, but it seemed rather futile to me. Is this a bug or is it just in the game and cant be fixed?

I've seen them leave and reenter a city once or twice, but never over and over again. That's weird. Though it is probably tied to the hardcoded AI behavior.