Lies. The mint employee could have had a time machine and purposefully made this error with a 2017 cent in 2015
Unfortunately, not everyone understands, or realizes the intent of a well placed "smiley". Gets me into trouble often. But I show "them" by never learning from my mistakes.
That's a plating blister starting at the lower part of Abe's bust leading up to the 5 and stretched copper plate that .. if you include the vertical part to the left of the 5, doesn't look like a 7 but looks like a lighting bolt under the 5. If you ignore the vertical part (why not right, because we have to associate it to a number thus disassociate anything that detracts from that) then it looks like a flat 7. But it's not, it's a zincoln.