Motto: If it seems to good to be true, it probably is.
Fielding wroteMy LB button has stopped, remapped to one of the buttons on the back so I could get around it. Unsure as to what is causing yours; could be something has snapped inside and is permanently stuck down?
I've fully opened it up checked to see if it was something blocking the connection like a screw, nothing. I searched up what it could be & as I thought i think it may be the hall sensor. It's tragic that I don't solder anymore, or I could've fixed this. £35 repair it is :/