Are slam fires common in an AR?

[HONDO]

I’ve had my Grendel doing unexpected three and four round bursts but I don’t think it was a slam fire. Like LR55 it was more of a match trigger/Recoil/lack of shoulder contact type of issue. (Poor form/free recoil) I was surprised but no one else at the range batted an eye lol. Never had a slam fire in any of my M1A’s or my Garand either but old Ithaca 37’s sure are fun to slam fire