Hi, Bill!
I don't want to be a "me too" kind of guy, but after examining 13 slides, Fastbolt's description is right on the money.
Newer slides, produced after circa 1997, certainly display a consistency with regard to the jagged tear-out in that area.
It seemed to me the plunger was sufficiently restrained and the ejector was in no danger of catching on that edge.
I also had a feeling it was akin to the thinning in the recoil spring tunnel that Fastbolt described (cosmetic rather than dysfunctional).
But it's nice to have official verification.
And I gotta say, under "stoopid-high" magnification and resolution, that tiny fissure looks like the Grand Canyon!

John