I’ve owned the gun since new. All springs and parts are stock on the slide besides the slide itself. Which is brand new, never fired. The slide is from JandL Machining Works. All of my old slide parts were swapped into the new slide. 3k rounds through the internals.Have you owned the gun since new or is it possible someone has swapped some parts out in the past? Are there any aftermarket parts on the gun including the slide cover plate? Has the gun been shot a lot or relatively new?
Assuming the gun has some use and is clean - based on the level of inspection you've done I'm guessing there's not any obvious carbon build up.
If you're certain the parts (extractor, firing pin safety and extractor depressor plunger) are correct for the gun I would suggest starting with replacement of the Spring Loaded Bearing (P/N 2714) and Extractor depressor plunger spring (P/N 33522). Be sure the Extractor Depressor Plunger is turned the right direction - metal against the Extractor and the plastic Spring Loaded Bearing against the Slide Cover Plate.
If that doesn't work my next step would be to replace the Firing Pin Safety (P/N 77) and Extractor (P/N 1895)
If you shop around the total cost on those parts should be in the $20-$25 range. Glock is great about keeping their spare part prices down.
Spring loaded bearing and depressor plunger both positioned correctly.
What really baffles me is that when I pull/push the extractor outward I can visibly see the safety plunger click out a tiny bit, locking the extractor outward. It does not take a great force to push the plunger down to release the extractor back to position.
The extractor depressor plunger is not bent, nor is the spring. No visible damage to the spring load bearing as well.