Twice, we have had 20ish minute times when audio on our system starts sounding like a cell phone call in bad coverage. It is an internal issue. It can be heard on CO and IC calls alike. The system is giving me no errors or any information. I do see spikes in CPU usage to 100%. It consists of Application and User. I don't see a way to track down the cause of the spikes. We've done a soft reboot, but it happened again. I plan to do a hard reboot in the morning. Can anyone help me track this down?

Is this a CPS that you are talking about. If so, are Automatic Updates disabled in the Services.

I've also seen weird audio problems when the ribbon cable between cabinets has gone bad.

This is a 5600 (MiVoice) not a CPS/VPU Axxess system.