This appears to be a bona fide smear error. Found right on top just as it sits, given by teller today.
its usually the first note. it happens quite often. i have tons of them from working at a bank and going through new straps of cash. i actually have sold 3 or 4 notes similar if not more sold on ebay in the last few weeks. here are just 2 examples. the $1 has already sold and the $2 is up for sale right now
i have seen whole bricks of singles were every strap the first note had the ink smear. they are nice but far from rare and not really an error
