1911 Wheat Cent with notable anomaly on both sides. (Indian 1c error and Lg Cent planchet(?) added.)
I don't much post here anymore, but someone whose opinion is based on decades of professional numismatic experience said that he believes this to be an 'incomplete punch error, with mottling from poor alloying'. He suggested posting it here for the opinion of Mr Weinberg, if he should see it and wish to comment.
There are also a couple/few others here on this board with a lot of experience in error coins. Their opinions/musings of course are welcomed as well, with 'Thanks In Advance'. (I have several old errors/possible errors and the expense of certifying them means I need to do as much 'homework' as possible before picking which ones to send in.)
Note the reverse, at left, where the 'line' meets the rim. It 'vanishes' then reappears up on the rim. That seems, to me at least, to indicate that the 'line' was not punched/cut into the coin after striking, but that it had happened before striking.
I remember when the 'PC' in PCGS stood for 'Professional Coin'...