Currently there are 2 buttons to leave a Consult Call (as the consulted agent), but only 1 of those will notify the Primary agent that they have left the call.
If the consulted agent uses the (Red door arrow) Leave Call button on the Communication Panel instead of the Chat pane, it will not notify the Primary agent.
The explanation for this is because the consulted agent is still in the chat conversation, and has not truly left until closing their Session tab.
It would be helpful for the Primary agent to see when the consulted agent has left the voice call.
Also if the call recording is being reviewed, the message should appear on the conversation transcript (as it would be consistent with the other method of leaving a consult call).