simple-peer: "Cannot set remote answer in state stable"

Hi. I switched from native WebRTC to Simple Peer, hoping a library would already control webRTC’s pretty fragile state machines.

I am developing an app for online conferencing and need to heavily connect, disconnect and reconnect various peers.

connection works flawlessly on first attempt. After closing the connection and trying to reconnect, I get the error Cannot set remote answer in state stable in latest Firefox, or DOMException: Failed to set remote answer sdp: Called in wrong state: kStable in latest chrome (chromium)

That behavior is quite annoying. I am looking for a way to control peers. Disconnecting should really disconnect peers from each other without any leftovers. It looks like the ICE-Servers are still expecting the peers to have a stable connection still?

When a connection is closed I call peer.destroy() and null my peer-object. I hoped that is enough to completely clean up, but WebRTC (or rather the ICE magic) is not really behaving deterministic.

here are some code snippets:

//connects to a client
//target: ID in OpenSlides
//offer: bool. should be true if initial
function connectToClient(target, offer, video) {
    var peer = registerClient(target, offer, video);
    var doSendVideo = false;
    if (video) {
        doSendVideo = true;
    }
    peer.on('signal', function (data) {
        // this is sending the given JSON to target over a python server
        Notify.notify("signalling", {
            id: operator.user.id,
            signal: data,
            video: doSendVideo,
        }, [target]);
    });
    return peer;
}

//registers a new client
//returns a client if already exists
function registerClient(id, initiator, video) {
    console.log('registerClient: ', clients);
    var peerConfig = {
        initiator: initiator,
        stream: video,
        tickle: true,
        reconnectTimer: 2000,
        iceTransportPolicy: 'relay',
    };

    if (clients[id] === undefined) {
        clients[id] = {};
    }
    if (clients[id].history === undefined) {
        clients[id].history = [];
    }
    if (clients[id].peer === undefined) {
        clients[id].peer = new SimplePeer(peerConfig);
        setupPeer(clients[id].peer); //this is just setting up the peer.on('xxx')-stuff 
    }
    return clients[id].peer;
}

this will be executed on the other peer. Ignore video for now

var signallingCallback = Notify.registerCallback("signalling" , function (notify) {
    if (!notify.sendBySelf) {
        var clientInfo = notify.params;

        if (clientInfo.video) {
            getMediaClient(clientInfo.id, false).then( function (peer) {
                console.log('getMedieClient, peer, video: ' , peer);
                peer.signal(clientInfo.signal);
            });
        } else {
            var peer = connectToClient(clientInfo.id, false, false);
            peer.signal(clientInfo.signal);
        }
    }
});

I hope somebody can help me or suggest something.