Possible 2017 series $20 misprint error [Risolto]

Hello all, I got this bill in my change today and it seems to me like there's some kind of printing error. It seems like the black ink is underneath the eagle and shield stamp. I figure something like that would only be possible through a minting error but I'm not very familiar with errors on notes so I'd like you all's opinion on it. If this is an error, does it add any collector value to the note or would it just be worth face value? Thanks for reading my post.

We see these traces of teller stamps all the time on many of the paper money forums.  Here's another similar thread on CCF.  I'm note a chemist but its likely due to the viscosity of the teller's ink that it has sunk into the note & then gives the appearance that it was underneath certain 2nd & 3rd printing elements.  Not an error & banknotes have nothing to do with the “mint” (they're printed at a printing facility - just FYI for future).

I agree, it is part of the edge a bank stamp. 
Although it did not adhere very well, there are traces of the ink visible on the eagle also.

Thank you both for your input and information. Seems like it will remain safely in my wallet until it's time to buy tomorrow's lunch. Have a great day.