I was send issue to Socket.io on GitHub.
This problems not only in Tor, with VPN too (every 10sec alert about bad connection on forum).
I hope this probmel have solution and it's can be fix with change configuration of socket or Nginx on NodeBB. But if it's not, this is bad news for people who life in country with censorsheps and they wants use NodeBB for freedom communication.
Polish Observe GIF