The only thing I have experienced is the game claiming I need 1 more AP and refusing to let me do the action if I don't have that 1 more AP, but never actually consuming the 1 extra AP it claims to require when it actually doesn't.
I also have a problem with the skillbook, which I had been regularly using, where I needed 1-2 more than the required AP to use anything in the skillbook. It simply would never let me use a skill from the skillbook if I had the exact amount of AP required. Using the skills from the skillbar would never experience this problem, so I ended up moving things on and off the bar to use them. Again, it never actually consumed more than the proper amount of AP.
