He's never had to engage in those behaviors with you, because you provide him with a better fit. In other settings, especially those that have something in common with his former preschool (lots of other kids, a teacher), his experiences have taught them that these behaviors function better than any other tools available to him. If the new environment sets about to teach him that,
1) these behaviors are not functional here, and/or
2) there are additional tools that will be at least as effective,
he will eventually abandon them. It sounds like the new dojo may believe that he has a plan in place to do that.
It will, of course, be work, but he is young, and, as much as it may feel like someone should have caught it sooner, really, this is fairly early in the process, and I doubt that the behavior is that firmly entrenched.
