In my Glock Armorer course today (my 4th time through) one example of the problems with non factory parts he cited was an example where he had personally inspected a gun at the request of an LE agency in the SW U.S.
A swat officer had been injured by a dropped gun that discharged and hit him in the lower leg, thankfully without breaking bones or any life threatening consequences.
The pistol in question had an overwatch precision trigger in place, one that used the factory trigger bar.
However when he performed a test on the gun in question, he was able to get the lower (without any upper in place) to allow the trigger bar to push off the ledge of the trigger housing with the trigger fully cocked by just depressing the "cross" area of the trigger bar with the trigger set fully forward. What he pointed out is that the geometry of the trigger shoe itself had changed the position of the factory trigger bar enough to make this possible.
Having a few Overwatch triggers myself on gamer guns, I came home tonight and was able to replicate the test he described myself on a Gen 5 with their Polydat trigger on their polished factory trigger bar. A second nearly identical gun with the same trigger bar would not fail the test.
This is probably not a huge issue on a gamer gun but one of these things will not go in any of my guns deployed for self defense.
The only thing I am taking from this is that just because some aftermarket trigger maker for Glocks used the factory trigger bar, that does not mean you have a gun that engages all the normal safeties....or is there something I missed in this?