iOS 10 issue I've had, haven't heard of many others with it? When you answer incoming calls if it hasn't been rebooted in a few days -- the call timer ticks but

iOS 10 issue I've had, haven't heard of many others with it? When you answer incoming calls if it hasn't been rebooted in a few days -- the call timer ticks but no audio happens. Press the keypad/speaker/etc buttons a few times and the phone locks up and requires a hard-reboot. Hangup button seems to work if you do it within a few seconds, otherwise the phone locks up. Anyone else have this happen? (Carrier: EE in the UK)