I do not know exactly what you are referring to when you mention your son's immaturity in the classroom. He may be acting out for attention because he is frustrated with the curriculum. He must obey classroom rules like any other student and he should receive appropriate consequences if he does not. However, to take away his enrichment is like taking away other students' regular assignments if they misbehave. Since that probably doesn't happen to other kids, it should not happen to your son either.
You need to ask yourself these questions: Is your son a happy kid? Does he have friends? Does he play or participate in sports with others? Does he still like learning? These are important concerns. If the answers are no, then you should consider counseling to help him with his immaturity and social skills problems. If his behavior is interfering with his learning, then his behavior is a concern that warrants attention. I still maintain however that much of his unhappiness could stem from not being challenged. Rather than just speaking with each new teacher at the beginning of the year, I think you should give them a copy of the book Teaching Gifted Kids In the Regular Classroom by Dr. Susan Winebrenner. It contains easy suggestions for enrichment that are low or no cost. You can also share this email response with the school if you like. I hope you find this data helpful. Good luck.