One other note, that's why alot of hunters wait to use pits until they're a little older, and you've had more time to let them mature mentally.
Not that this is how the dog in question was raised, by any means, but....All catch from day one and no social skills greatly improves your chances of having a problem dog......like raising Mike Tyson in a cage, throwing some food in now and then, then asking him to carry himself "professionally" when you let him out.... you're already dealing with something a little twitchy to begin with

Has the owner been "
really clear" to the dog that he is not allowed to do that? Sometimes you've got to go to level 11 to make a point with those dogs.