This started in May 2020. It could have started with the latest update. Has never been a problem. During the day, I have the ringer volume set up, then I start missing calls and find that the volume is turned completely down. I uninstalled HiYa and that didn't solve the problem. I have tried clearing cache on Various applications, haven't found the culprit. I use Do Not Disturb but was using that prior to this problem starting. I use Zedge dial and notification tones, I just changed those to Media Storage sounds and will see if that solves the problem. Anyone else seeing this on a Samsung Note 10?