the dept I work for issues G21s.

I recently got them to turn in 19 year old 2nd Gen G21s which some were not passing the safety checks due to wear.

I am not sure what issue you speak of exactly but I have seen misfires with Glock 21 with a slow controlled press and the same gun will fire with a hammer stroke of the trigger.

the firing pin safety actuator on the trigger bar is not timed correctly and not moving it out of the way or there was some frames with higher set slide tabs in the frame which made the slide higher and of course the same misfire would occur with a controlled press of the trigger.

Glocks fix was the plus trigger bar which I was told originally had a taller firing pin safety actuator but at a recent recert...I was told that was not correct.

We recently had a few G21s with TLR1s start to slide lock back prematurely with Gold Dot 230s. some did not and these were either 3rd Gen G21s. A newer SF with a TLR1 ran ok.

I carry 1911, but if they make me park my personal....I will carry the G21SF or my G35 on duty.