Basically our agents will be on a call for some period of time and then the audio on the agent's side will drop out.  They cannot hear the caller, but the caller can here them.  This goes on for a duration of about 30 seconds.  We had a TAC case open...

We are running Call Manager 11.5, Jabber 11.9.2, and Calabrio One Suite 9.3 AQM.   Our headsets are USB, Plantronics C-520.

Did TAC ever come up with a solution?  We are experiencing this and TACs suggestion did not fix the issue.