Volume setting negates itself and/or dissipates with daily use

Im currently using a Z10 with the latest 10.2.1.2141, but I also found this problem with 10.2.1.1925. One bug that keeps presenting itself to me is that the no matter what volume level I set, it doesnt stick over time with regular use. It will go to a quieter sound, almost inaudible levels even with the slider turned all the way up. To resolve temporarily, I have to turn the device off completely then restart it. Upon reboot I will check the slider sounds and make sure its full sound level. After a short while it will go back to quiet tones. I have observed this behavior on 2 different Z10s that I have but not my Q10.

Im wondering if I'm the only one here that has encountered this, but feel I shouldn't be as I have attempted many different ways of installing leaks. Wipe/install, no wipe/backup/install/restore, no wipe/no backup/install all with the same results.

Im struggling for ideas and I havent really seen anyone mention this issue with respect to basic device volume settings. Thank you for any suggestions.

Yes it is happening, I basically just reboot the phone with the volume rockers and it should be back to normal for a few days.