Rare $100 Bill With Green Security Ribbon?

Hello. I came across this bill and can not explain this. I work for a bank and came across this note. On my own time after my shift, I used my own money to exchange the bill. It is now in my possession.

The green ribbon immediately stood out. We ran it through our magnetic machines, ink pen testing, black light, our internal currency verification guides, and we called the Secret Service as well. The bill is legit and cannot be explained.

As you may or may not to know $100 bills show a red security strip one held under a black light but this one on the other hand had two bright white dots and no red strip, but we do know the note is not counterfeit. It is real.

I contacted some local coin shops and nobody has ever heard or seen this. I did so much research and can not find a single answer. I did come across one forum on here from 2014 though of a similar situation. I am the 3rd person I have heard about having this bill.

On the back is also what looks to be printed 'SS'. We zoomed in at work and it is not pen, but printed into the fibers.

I am going to contact the US Bureau of engraving and printing monday morning. I do not know what it is worth or how this is handled. Please give insight. I can provide more photos through email.