After updating firmware on the CX600's to 4.0.7577.4372 we now have an intermittent issue . User gets an incoming call, places call on hold and when retrieving the call the audio is very slow. I have tested on CX700's and 600's with older firmware and the issue does not appear. I also moved up to 4.0.7577.4387 and the issue is still present. Checking the Lync reports and using Lync Snooper everything looks fine. The current work around is to place the call back on hold and then click resume again.
Has anyone else seen this issue and any luck getting it resolved?