Penal unit mission doesn't advance

[Ba5]

This is the mission where you sent a bunch of Russian prisoners to capture a church, and then a hill after that. I clear the entire map of enemy soldiers, move my units up the hill, then nothing. Then I restarted the map, and nothing again.

What do I do now? I must be doing something wrong, no way are the developers so stupid that they missed an entire mission not working.