I have an KX-TA624 that I installed in my home with seven KX-T7030 phones. Two of the phones have the same problem. If you attempt to call them over the intercom from another phone and they're in the hands-free reply mode, you hear a loud growl in the calling phone. If the person yells, you can hear him above the growl. If he picks up the handset, the audio is perfectly clear. I have plugged a known good phone in this room and it works correctly. Other than replacing the two bad phones, is there a way to fix this problem?