I imagine it's a glitch caused by the way the demo "redirects" a user to a room. Probably you hit back and then get redirected again. Sorry about that - it's not intentional. I'll let the team know.

Wen Bo from the Realtime team here!

That back button glitch is specific to the demo. We had to do a few redirects based on Presence sync and load balancing each room. I'm sure there's a better way of doing it and will seek to improve it when I update it. Sorry about that!