While using MOC client 2007 R2 and users often complain that when they answer a call on the phone it automatically gets put on hold and it doesn't matter they to answer using speakerphone, headset or headset. If they kill MOC client on their computer and restart it the problem goes away.
I have reproduced problem on few computers for testing and researched on issue.
-> Only one call is active the other calls are put on hold automatically by communicator, because by design OCS 2007 can only have one active call at a time, it puts other calls on hold.
The call was established on MOC 2007 R2.
When there was a new call coming, MOC found there was two call active so it sent HoldCall event and call put on hold.
Resolution at this point found -
1. Only solutions to quit MOC 2007 R2 or remove RCC from users account.
2. Upgrade the Avaya or Cisco software (soft phone).