In the past, I have noticed times when I can no longer adjust the volume for messages on my phone and I have restarted it to resolve. Today, I experienced the issue where the volume would remain high on a locked screen no matter where the level was adjusted to.
In Settings>Sound, the option for Change with Buttons is on.
I was in a message thread and adjusted the volume with the buttons and the Ringer icon appeared. As long as I remained in the message thread, the volume would track with my button adjustments. If I locked the screen, the volume would return to a high setting. I wondered if it was somehow tied into the phone volume.
I placed a call and then adjusted volume and the Phone icon appeared. The volume here was still high compared to the Ringer/Message volume which I had set at minimum. I adjusted the volume on the Phone down slightly and then tested message volume again.
At this point, the Ringer/Message volume appeared to sync and I was able to adjust message notification volume with the buttons again and the volume adjustment remained in place on a locked screen again and not just while I was in a message thread.
This is an iPhone6S Plus on iOS 9.3.5 (13G36).
This issue is intermittent in nature, but does recur. No frequency for recurrence is established.
I searched here and did not find any issues that seemed to match this exactly. This appears to be a bug, does it not?
