I found this article, what kind of error is this http://coinedformoney.blogspot.com/2006/01/20-dollar-bill-error.html
Patience, young Jedi, the paper money section does not get as much traffic as the coin section of this site. Someone will come along with an answer.
Hello, this is the owner of CoinedForMoney.com and that was a 6 year old post. Since then I never saw anything else like the commenter described and I suspect she had an a fake. There has been no error notes auction that mentions these. I would not know what to call them since I am not sure at what point the yellow 20s are added on. It would be nice to know what happened but comments like hers rarely have a follow up or update.