I have lots of those and all work flawless.
It's a simple construction, not likely to break.
The pin is going all through, moving freely so it's not sticking out a certain amount.
It's spring loaded by the capsule's pin.
The pin has a cave on top and a tip on bottom. If these are still there it's intact.
Maybe the capsule's pin does not stick out far enough.
Or the very fine capsule/body mounting threads are in bad condition and it's not possible to screw the parts completely together.