Conference Phone Audio Issues

[Montauk]

Hi there. Ive reached my limit on diagnosis for this issue. Im not sure where to look next. We have a CP920 at the center of a round table. It is being used to host conference calls during Covid-19. The audio is ok. It is clear. However, from time to time during the meeting there will be an abrupt cut in the audio. Listeners lose a word or two. The phone's microphones seem to quietly come back slowly gaining their abilities to catch the speakers voices. I have checked 3cx firewall checker and everything is just fine. There is no unusual load on the network during the meetings. the conference phone has been put on a vlan. I have shut off all autodetect switch port settings. The phone is PoE. I have a T4 series phone with a similar run and it works great. The only difference is the microphone. Is this phone broken?