Hm. I suppose the question to ask is if anyone else has experienced this problem, then. Maybe my version or computer is just weird.
The same thing just happened in Battle with Ebon Raban, actually. He's supposed to order the block of nine troops near him to move after a few turns, right? That worked as usual the first time, but when I lost and retried the battle, that never triggered. The crossbowmen chasing Annel Stormhunter didn't appear either (though Annel himself did).