Omni - didnt you say in the game thread the the Ashen Angel became Enslaved by the Tart Chains? If so, I wonder if you enslaved it, and then unwittingly killed it with your Holy Avenger attack? This in turn cause some kind of wierd routing to kick in?
The Ashen Angel didn't rout, but I don't think that's what this bug is about. It could be that Ashen Angels don't rout, or that this is one case where units would only rout the next turn. The "XXX army is routing" message is probably triggered whenever one of the global routing rules is called for, even if there aren't any units that would, actually, rout in the battle.
Also, I think sometimes it takes a turn before all squads actually rout.