Experience With a Clashed Proof?

Has anybody encountered a clashed 19th century proof before? Seems like such a thing should not exist. The coin was graded by our hosts as a proof and had the diagnostic markers for a proof, but the central reverse was boldly clashed.
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That would be cool to see!
Dealing in Canadian and American coins and historical medals.
Since clashing (or "blanking" as the mint called it) was a die-to-die event, it could occur during any type of coin production.
Dies used for proof coins were just normal dies that had been polished. They were as likely to have defects as any other die.
If the teeny weeny serifs or extra thin letter bits on the hub break off, those breaks will be transferred to the dies before they're prepped as proof or business strike dies.
Keeper of the VAM Catalog • Professional Coin Imaging • Prime Number Set • World Coins in Early America • British Trade Dollars • Variety Attribution
Seem to recall seeing a few over the years, but couldn't say what they were. Probably minor coinage like this two cent piece. They did not get the respect that gold and silver coins did.
@RogerB No doubt it could occur, but presumably it would have been caught very quickly.
One of the proof diagnostics for this date is the missing serif on the D. I guess this was fixed before switching to circulation-strike production if the same die was used.
As for TPGs mixing up proofs and circulation strikes, I have seen a handful of business strikes called proofs and vice versa. Usually minor coinage from 1860s-1880s.
Dealing in Canadian and American coins and historical medals.
A suggestion is for someone to compare coins struck per die pair, with die defects visible @ 10x. It might be much greater than we presently assume.
I suspect this is a Proof die that was taken out of service to strike coins for circulation. The weakness in the fields and the rims are not normal for Proofs. Several 1865's are clashed in this fashion. Non are Proofs.
If the TPGS call this a Proof, they must know something.