Why is my phone's volume going down and then going back to normal?

[Android Central Question]

I've had my phone for a few years and it has not done this until recently.
I will set the volume at where I'd like it then it will go down after several seconds, then it will go back to where I set it. This cycle continues with the duration of time between volume changes being random.

This happens on all apps and through the phone speakers, through earbuds, and through Bluetooth speakers.
Sorry if this has already been asked, I'd really appreciate a way to fix this.

 

[B. Diddy]

Did you also post this? https://forums.androidcentral.com/a...nging-without-my-interaction.html#post6257697