I've read that page before. I'd like to think that I'm familiar with all the security features. It's the reason I even thought of using a UV Pen light to quickly check my bills and came across this anomoly.
I've gotten several $20's now, all from Fifth/Thirds Bank, where the security thread floresces Orange instead of green. They aren't even the same series. Unless I get a CU next time, I think I'm going to start handing them back to the cashier and ask for a new one as I've gotten enough to work with to try to authenticate if they are counterfeit or mule notes.
Everything about these bills feels, looks, and smells real (yes, the ink in our money has a distinct smell to it). If these are extremely high quality counterfeits, I don't want to get stuck with them, but if they are genuine mule notes, I don't want to pass on them. Any suggestions on who I can talk to, or show them to, to get a second opinion?
As a side note, I do like that the thread in the $50 bills is wider, much easier to check now. I wish they would make the thread for the other denominations wider too.