What would cause a bumper button to not work

I have a PS5 Dualsense remote with a suddenly non-functioning R1 button.

• No physical damage to the remote from dropping/excessive force has been exerted
• No water damage
• The black plastic part of the button is in the correct position. Removing to access the silicone part of the bumper button and pressing with a pry tool/screw driver does not work
• R2, L1 and L2, as well as all other functionality is perfect
• The remote is a v1 remote

I've tried disassembling the remote and investigating, nothing out of the ordinary to report and I'm at wits end. Any guidance would be appreciated.