Sound not working in "gnome-twitch"

I installed gnome-twitch snap today. It can play video, show chat but there’s no sound.
Sound works fine in other places like falkon snap.

Do I need to connect any plug/slot? The snap description says nothing like this.
I use Ubuntu Xenial
flathub version of GNOME Twitch works fine but its 0.4.0
Snapcraft version of GNOME Twitch is 0.4.2

Output of snap interfaces gnome-twitch

Output of snap interfaces falkon (for comparing)

Indeed, it looks like a bug in the snap. It tries to open alsa’s and is failing … @diddledan should probably add libasound2-plugins to the staged packages?

(could you report that on ?)