I just resigned from a game. Immediately, a voice said “challenge received”, but nothing seemed to change in the UI – no notifications, etc.
What happened here? Does this have something to do with the Rematch button (which I’ve never attempted to use)?
In 2014 there was a topic on this:
Maybe this is related to that.
Well, we beter wait for a mod to sort this out 
This happens to me from time to time. Where do I go to respond to the ‘challenge received’ voice message?
Bumping this. Today, I finish a game, and hear “challenge received”. I have 2 browser windows open on the game: Safari and Chrome. In Safari, I see a Challenge in the notification bar and on the home page. In Chrome, I get neither.
Anyone else noticed challenges working (or not) in Chrome or other browsers?
I think that there is one way that this can happen which is when the server restarts after an updated.
I’ve definitely seen some “out of place” notifications like that when this happens.
If you are experiencing this rarely, then maybe just think to yourself “Oh, cool, an update was applied to the server”
Server updates are never more than one or two per day, and usually rather less frequent than that, so if is happening more often then it needs more digging into, because that would mean it;'s something else.
(It still needs to be fixed, even if this is the cause, of course).