I'm assuming that you have shot it yourself and everything operated fine . . .? ? Almost seems mechanically impossible. . .to be random at least . . .
Somehow the trigger is going to the rear and the striker safety block is not getting disengaged thus not firing in my holster. I'm not the original owner but it has had no mods done. trigger is 7.5lbs.
I have probably 350 rounds fired so far through it.