We just bought a couple of the ocean reef FFM's with comms yesterday. We tried them in the pool today and found one of the masks emits a high pitch squeak most of the time when air is flowing through the second stage. Is there anything to be done by us without having to bring it back to the shop? We've tried adjusting the adjustment knob and swapping it to a different first stage. The affected unit squeaks on both of my firsts (scubapro mk25) and the other unit does not squeak on either first.