sometimes when I switch my phone to silent, the phone switches to ringer mode itself and then back to silent randomly. I wonder if it's a software issue with 9.2. I haven't experienced this before 9.2.. I'm having the same issue as this guy here, and he's using a plus.
https://discussions.apple.com/thread/7387913?start=0&tstart=0
https://discussions.apple.com/thread/7387913?start=0&tstart=0