I think we are all getting this problem. I have had four enquiries and reservations in the past week that have not come to my phone. Fortunately I do check by PC email frequently and have been able to respond and apologise for the delay in each case without any serious issue. The first couple I though were just one offs but it looks like this hoary old 'chestnut' has come back to haunt us again!
@Lizzie gave us the heads up on what to do. Turn off your notifications and push settings, log out so the change is accepted and then log back on again and reset your notifications.
This is a re-occuring problem and has been with us since I have been hosting in early 2015.
It would be super nice if someone in programming would actually scratch their head and wonder if this little 'glitch' could be costing Airbnb money!
Cheers......Rob