It's a simple spring inside that isn't making electrical connection, looks like we have faulty parts.
The tolerances are pretty tight, I'd guess a few thousandths of an inch difference from a crack in the housing of the switch could cause it to fail.
Oh yeah, I got it, the plastic tabs just to the outside of the actuator which hold the body of the switch to the metal soldered to the board get stretched over time and create too large a gap for the throw of the spring to activate the circuit. Bad design!
The holes in the back of the switch create a weak point where the plastic is able to bend and potentially break with the force applied in the center of the switch while being supported at it's outer edges.
Edited on 2/23/2021 at 9:17 AM. Reason: