Only since updating to iOS 9 on both my iPhone 6 as well as my Wife's 6 Plus ( both excellent & generally trouble-free devices ) have I we had an issue with the display of the screen when an inbound call is missed. This is, when this screen appears, probably 30 % of the time, one can't dismiss it or in any way go beyond it. One must actually turn the phone off ( soft reset ) to see the missed call notification and /or use the device. We are both now on 9.3.5, but this glitch or bug has been popping up since upgrading from the original iOS 8 which the phones shipped with. The prompts for 'back' , 'Send a Message' , 'Cancel', or 'Accept' are intermittently totally unresponsive. Both phones have been hard reset several times over this issue ( and a few others ) and are normally updated OTA ( whith the exception of the iOS 8 to iOS 9 transition last fall which I did in iTunes as is my habit for non-incrememtals. Im happy to simply wait for iOS 10 before doing anything drastic, but wonder if anyone out there in iPhone-land has seen this behaviour. ?