I also got a bugwhich is quite a problem, sometimes after a battle my prisoner Count goes to 0/0 so I can't capture any of the prisoners I get, and I have prisoner management lv 3. Sometimes it works though, kind of annoying, especially when I need the prisoners to restock my army after som casualities.
Edit: Only seems to happen while I faint in battle, maybe it's a feature I missed but seems like a pretty strange one.