There is a bug with bosses and mobs natural attacks and the usage of their pips.
When a boss or mob uses their natural attack, (visually) it shows them only consuming 1 pip (or 1 power pip).....and after the round is over (a new round begins), they lose another pip (or power pip), and then gain one.
So they are actually consuming their pips, but the bug only shows they have consumed 1 pip, then the next round they consume the other pip, then gain one.
I have been questing for a few weeks through different worlds, from wizard city to azteca so far, and it has done this in every single world.