When I don't answer an incoming call the ringtone volume increase gradual to maximum. Next call ringtone volume increase to maximum or near the maximum from the first tone. That change also ringtone volume settings in /sounds/volume/ringtone which stays in increased position. The same thing happend when I silence the incoming call ringtone with one press of vol- button. Sometimes volume of ringtone incoming calls increase to max and starts on maximum level from the first ring but ringtone volume in settings is not changed. I don't know what reason it depends. Problem noticed also in previous version MIUI from 7.2 including fake roms and china stable. I've tried 3 factory reset. Maybe I can fix this annoying issue with option thats disable increasing ringtone volume but I don't know where to find this settings?