Actually, it looks like a die scratch. Pretty serious one at that. Can you post an image of the entire obverse?
I'm in the "die scratch" group. Or possibly a "strike through". I can't see it being a die crack otherwise the MM would be cracked also. As for a "linear plating blister", I think the MM would also show some effect. The "D" is too clean.
How would the die crack go through the loop in the D without just chipping all the way off and filling the D completely?
zincoln .. always expect the unexpected. linear plating blister .... you can see a couple more next to the 5. Can we see the entire coin front and back ? This really should be done first and foremost as usually the rest of the coin can also tell the story.
I have found that several of the zinc coins have awkward anomalies. I have yet to find any of significant value other than face. Plating blister sounds right to me also, sorry.
Here's a die crack on a Washington Token I bought a few months ago. When I bought it I had no idea it had the die crack until I looked at it last week! Nice surprise for me!
the copper didn't bond well to the core and is now lifting up seen many of these in change seen some that have tiny bubbles on them then others have huge bubbles
Actually that is a further die deterioration issue, That is a shettered die. Withhout looking further it has four seperations on the die face. Split die face? @mikediamond