I’m experiencing the opposite of what the others in this topic are experiencing.
My volume up button is quite unresponsive more often than not. It requires multiple presses, sometimes harder presses, to react and register a volume up press.
The volume down button works without any issues and feels a bit lighter to press than the volume up button.
I already tested in the CSD tool - it took me more than 5 presses of the button to register 5 presses of volume up. The other buttons worked normally.