Mine was always falling out. You don't need to do a complete strip. If you can’t wiggle the firing pin back into position with a paper clip or similar, you can retrieve and reposition it by removing the screw on the right hand side and manipulating the safety barrel or removing it. Be aware there is a sprung detent ball bearing under the left side, and an extra safety spring on the safety barrel if it’s a later model.

Completely stripping the CP88, removing the machine burrs, polishing up the mating surfaces with 1000 grit, and lubing is well worthwhile in terms of smoother performance though.

Excellent guide on UBC forum:

https://www.tapatalk.com/groups/umar...ion-t2309.html