MI set to Aggressive/Front. They step forward, nobody else does, 1399 arrows turn my unit (#12) into a pincushion.
So... I guess they let you down after all, huh?
Anyway, that's not a formation failure. That's an MI logic failure. I thought that had been fixed with the latest changes to ranged units that make them fire for as long as they have a target, rather than advance. Maybe that hasn't made it to stable yet?