Nexus 5x - volume decreases automatically

[wsl543]

Hi,
My Nexus 5x (android 8.1) has really annoying issue. Ringtone volume decreases after couple of seconds automatically. The same issue is present when turning on loudspeaker during call - loud and clear but after 2 seconds it goes 50% lower volume.

Recovery mode and factory reset did nothing. Is it hardware problem ?

 

[GSDer]

What happens if you open the Volume controls and just watch them for a few seconds? Do you see them move on their own?
Is it only the Phone volume that does this and not the Media volume? If that's the case then it's likely not a hardware problem.
Does it happen in Safe mode?
Do you have any Bluetooth devices connected? If so remove them all and reboot your phone.

 

[wsl543]

it's ok when ringtone volume is set mid strength. It's present when I crank it up. So it seems like weird speaker protection built in android 8.1

Media volume is also affected, loudspeaker during calls also which is most annoying.

Youtube video under chrome is loud as hell and nothing happens

No bluetooth devices, no headphones used