This seems like a state machine bug to me. If you consider what happens when you add a third person to a call: You start sending them everyone's audio! That's

This seems like a state machine bug to me. If you consider what happens when you add a third person to a call: You start sending them everyone's audio! That's the desired behavior and exactly what happened here. Except the client should have probably checked if the call had been accepted first. That's why I say it's a state machine bug: The "Send audio" function should have never been activated in state "waiting to accept".