Can you please verify the follow settings:
1. That you are using Agent Desktop Settings and have configured a Ring No Answer value
2. What that value is set to.
3. And that the values are set to required and not optional.
In short what I believe you are seeing is the Call Manager utilizing it's RONA setting and reclaiming the call for it's RONA treatment. Since the call was bound for an agent and the ACD intervened we would view this as a Abandon. Make sure that the ICM Agent Desktop values are at least 2 seconds less than the RONA on CCM.