Firefox with proxy: Mediasoup demo is perfect, but mediasoup-sample-app has a little issue

There is a very simple sampe app:

If I start a stream, then consume it in another tab, if the consume side is firefox and using a proxy, then I can never connect to the transport properly (in the webrtc tool, seems the ice has an issue, also cannot get the connected event).

However this works perfectly in the official demo.

Is there any trick?

Many thanks in advance!