[PvK]

Yep. A very simple mod will fix it, too. I expect that the commander just needs some undead leadership - not necessarily enough for the whole mob.

For example, some random events give forces led by a commander who doesn't have enough leadership to control the units who nonetheless start out under his command and work fine unless they get un-assigned to his command. Which is actually an interesting and not inappropriate limitation - they are under him do to an unusual event, and not only because of his innate leadership. And, he can't have an army of unrelated troops put under his command.

PvK