When the obverse and reverse dies slam together without a planchet between them the reverse die leaves an imprint on the obverse die and the obverse on the reverse die. (called a clash) Sometimes, another clash episode hapens and the clashing marks are then transferred BACK to the source die, a bit out of the original alignment, to create a COUNTERCLASH! (insert scary music here) Can be confused as doubling to an inexperienced eye.
Below are a couple examples of listed counter clashes.
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