Today my 2019 43RU7475 started auto setting the volume to 100 - it randomly does this while watching a show. I've tried updating software and resetting everything I could via the TV app.
This also happens when the remote has no batteries. With the remote, while I can adjust the volume downwards, I am not able to adjust it upwards. I confirmed this with a second Samsung remote control, as well. So, it seems the problem lies with the TV itself.
I just connected my SmartThings app (on my phone) and it too is unable to adjust the volume upwards (only downwards).
Never had a problem like this before...not sure what to do...
SOLUTION (for my situation): After a few hours of trying to debug what was happening, I realized that my Apple TV remote (the newest version) was the culprit. I confirmed this when I took it near the other Apple TV in the house. Buttons were sticky - the remote was essentially overriding changes from any other device.
So, inspect all your remotes (Google, Amazon, Roku, Apple, etc), as well.
