I have an iPhone 6 Plus and am noticing that the ringer volume will go back down to 50%. When I check the settings it's all the way up, but I have to use the volume keys to put it back to full?
I noticed that a year or so back. My bottom speaker on my iP 4 quit. No game sounds and etc. I could not figure it out. Called Verizon and they sent me a replacement. Before it got here, I went to YouTube and noticed the volume was half way. Checked the home screen and it was all the way up. Went back to YouTube and turned it up there. Problem solved. Sent the phone back to Verizon.Could it be that you use the volume keys to lower the volume from other apps? These buttons affect ringer volume too.
You can disable this in the settings. That way the volume keys let you only adjust the volume from apps and doesn't affect the ringer volume anymore.