I actually consider the K11 on this note to be the district letter and number that sits just above the Fed seal. Minor over inking is a popular question from new collectors and is often seen here along with miscellaneous ink stampings and general graffiti. It's typically not common but definitely not rare.
On the larger denominations (not $1 and $2 bills) but on the $5, $10, $20, $50, and $100, the note will have a letter and number designation that corresponds to one of the 12 Federal Reserve Banks. The letter of each indicator matches the second letter of the serial number on the note also. A1 Boston B2 New York City C3 Philadelphia D4 Cleveland E5 Richmond F6 Atlanta G7 Chicago H8 St Louis I9 Minneapolis J10 Kansas City, MO K11 Dallas L12 San Francisco. That is what has the minor ink bleed but I've never researched whether ink bleeds in this area in small size has any added value. There seems to always be value however if the seal has over inking. For the $1 and $2, the note includes a seal instead with the letter inside the seal that identifies one of the 12 Federal Reserve banks..