Why is my volume is fluctuating by itself?

[Sockslapped]

I have an LG G4 running marshmallow 6.0 right now. I've been having an issue where my volume will lower itself as if I received a notification, even when there isn't one, then return to normal after a second or two. It happens over and over several times a minute generally. It happens across all apps whether I'm watching a video or listening to music or whatever.
I factory reset the phone already and the problem still persists. It happens through headphones, bluetooth speakers, and out of the phone speaker.

 

[Morty2264]

Hi!

My would-be suggestion to you would be to do a factory reset, but you've stated that that hasn't helped. I'm sorry that you are experiencing this! Have you downloaded any music apps or anything else along those lines that may be causing the volume to act skittish? What about your volume keys - they aren't sticky or anything?