Release peer connection resource

My app has many tabs (not reload page), when switch among tabs, I stop communication by following code:

this.conference.leave().then(
                () => {
                    if(this.conference) {
                        this.connection.disconnect();
                    }
                }
            );

But when I check by webrtc-internals, I find many stucked peer connections with bytesReceived/bytesSent be stopped increasing. It’s not problem with bandwidth, but it doesn’t release these old peer connections.

Is it possible to release them thoroughly if I has left/disconnected an Jitsi conference?
Thank you!