I just had this happen to my PF-9. I was at the range doing some drawing from concealment drills. On my third mag, I got no bang when I pulled the trigger. Cleared the malfunction and continued shooting. I looked at the round and it had a strike on the primer. (It was WWB or Fed FMJ). I loaded it into my next mag. No problems. It happened a few more times so I stopped used that gun.
NOTE: I have had this gun for 3 years. This was the FIRST problem of ANY type. I have 1,500+ rounds through it.
I took it apart when I got home. I found a tiny peice of brass (like a hair) in the firing pin channel. Cleaned it up and will have to take it back out before I carry it again.