I would gander that the high frequency two-way data communication is likely screwing with the electronics in the AFCI itself. I'm guessing they were probably only designed to be used with 60Hz, so here is possibly another application from advances in new technology that AFCI’s were never intended to handle.
I would shoot the circuit breaker manufacturer an email so they can begin to make revisions to the next generation of AFCI and add another $20.00 on to the current price for their efforts.
