Happens sometimes in battles. My men won't stab they will just stand there in that "hold attack" mode and do nothing? Help!

Edit: After a little bit of testing I have found it is only the highlanders that have this issue. However they are the backbone of my army.

Edit #2: I was mistaken.
It appears to affect all bayonet using troops. and not just the Highlanders.

Edit #3: It is only this save. I started a new game and it worked.

Edit #4: I disbanded the arty and now it works fine!