That's weird how the toning follows, I don't see any separation of the planchet to call it a lamination.
I first thought die crack then looked closer and noticed it goes rounding all the way down to the rim. It looks like a "crater" to me is the best way I can describe it.
Looks like more of a stain than a planchet flaw. Don't forget that oil was placed on a lot of '43 Steel cents to prevent rust.