I have a one dollar note (2001) where the black ink was over-inked. By that I mean that the print, designs, signatures, etc. all are way too thick and stand out more than any other bill I have seen. The print looks ugly because its like the ink soaked into the paper making the letters thick. The top pic is a high res scan so click to expand it.
I would imagine that this note should have probably been replaced with a star note.
Is this an error?

