I had the same issue but stumbled across a solution today on my 635.
1 Turn off location services
2 Go into edge
3 Turn on location services
4 Go to Cortana
5 Access quiet hours via notebook
6 All the quiet hours settings were back
Hope that helps
I had the same issue but stumbled across a solution today on my 635.
1 Turn off location services
2 Go into edge
3 Turn on location services
4 Go to Cortana
5 Access quiet hours via notebook
6 All the quiet hours settings were back
Hope that helps