Failed to execute setRemoteDescription on RTCPeerConnection (TS client bug)

[sax]

We very occasionally see this error in Chrome:

Uncaught (in promise) DOMException: Failed to execute 'addIceCandidate' on 'RTCPeerConnection': Error processing ICE candidate

DOMException: Failed to execute 'setRemoteDescription' on 'RTCPeerConnection': Failed to set remote answer sdp: Called in wrong state: stable

This happens in the following (pretty-printed) code:

this.onAnswer = e=>m(this, null, function*() {
            this.connection.ontrack = this.onTrack();
            try {
                yield this.connection.setRemoteDescription(e)
            } catch (t) {
                console.log(t)
            }
        });