Greetings Il-Principe,

I could be mistaken here, but maybe it wasn't a bug. If you made the selection that you control both armies, but then right clicked on the opposing army to see it's composition, and then clicked "start battle", then the battle would start without you controlling the second army. If you bring up the details on the opposing army, you must then re-select the AI or manual control, as well as night battle. They return to the default position if you look at the other screen.

Does that help?

Strength and Honor

Celt Centurion