Two things, one "on topic" and the other an extension of the OP's coin.
Here's my contribution to "unusual" items.
At least I think(?) it's unusual.
You don't hear a lot about Euro coin errors.
A double clipped 2-euro coin complete with Blakesley Effect.
For the second topic it's a question.
The OP mentioned "almost CAMEO".
The question is, "What does the Mint do with dies used to strike proof coins?"
I believe only about 2000 proof coins are struck from those dies.
Do they then use them to make business strikes?
That would be one way business strikes could have a cameo appearance.