May be way off base here, but let's see...
I use a program called "Sound Profile" This lets me set a profile to be scheduled, so at night, it silents everything but ringer, day time, it turns on all sounds and vibrations, and it also has a widget where I can toggle between normal, vibrate, and silent modes. Well when I backed up this app's settings on my Note7 and restored them onto the S7, it decided to backup the Mp3's I had set for my notifications and ringtones. The problem was that it must have numerically cataloged those mp3's, because they were not the ones I had set. The app showed that they were, but they were wrong, and I had to reset all of those. Before I reset them, every time my scheduler changed, the sounds, volumes, and tones were all wacky.
Long story short, I had to go into each of my profile settings in this app, and reset my defaults. Since then, certain apps that I've silenced have now stayed silent without being reverted. So do you perhaps have some sort of app that is behaving this way?
