Just bought a new PF9 today.
Shot around 120 rounds through it.
Around shot 100, when my hand was pretty tired, I had a failure to fire.
I pulled the trigger, and it just clicked. Pulled the slide back to eject that round, and the rest of the rounds fired ok.
Would limp wristing have caused that?
Honestly, I don't remember. I ejected the round, and put it through the next magazine, and it shot fine.
Hard primer? Dunno. It's happened to me before.
Good tap-rack-bang though.

sounds like an ammo issue.
they were reloads, so it's possible.