Shield Mag "Bump"

[JLM]

Hi All,
Practicing draw and dry-fire this evening, and as I'm reloading my Shield to put it away, I notice one of the mags is different. It's one of the 7-rounders. No idea if it's one original to the gun, or one of the extras I have acquired.
There is a bump on the top right rear corner of the mag, at the rear of the lips. It's got a defined ring at the base so it appears factory stamped and not something done through handling. None of my other mags have this. Any idea of why it's there? Anyone else have this? It feeds and fits just fine. It's at the tip of the screwdriver below.
Thanks

 

[Lycan]

The forum's search feature had this as one of the results...

http://smith-wessonforum.com/smith-wesson-m-p-pistols/386182-new-m-p-shield-9mm-owner.html

The dimple appears to be normal on some magazines and shouldn't effect function.

 

[dereksfl]

I dated a girl with dimples..she worked just fine too! Shouldn't be an issue.

 

[shotguntom]

I checked all 6 of my mags, and no dimple. Really doubt it would have any effect on function.