Yep, you were right. It was fallbacking to ajax polling. I guess I'm just going to use CF in DNS only mode until they release their web socket support to other plans.

I've been reading several times that NodeBB uses websockets and therefore only CF enterprise customers may use it. However my instance of NodeBB works quite fine with CF's free plan (no websocket support apparently). I also don't get any errors in my log. Why does NodeBB still work then?