I see a long tail on the last 9 that runs through the mintmark but the image is so tiny I cannot tell if is a scratch on the coin (indented into...
Were there any clear diagnostics? Yes. There were some minor tool marks. Omega's dies were VERY good but they were not perfect.
There is not a term for it as far as I know. It is simply an unstruck or weakly-struck area of the coin.
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