Printing error involving the use of the wrong color of ink piecemeal in intaglio printing.
Part of the eagle, the place and date of issue, as well as the signatures and part of the circle in front of the king's face and the tip of his beard printed in green ink - such as the ends of the stripes on the right, or the top of the square on the left, below.
We see no traces of chemical interference here. Green ink is normally used for printing in other areas of this banknote, and here, as a result of a printing error, it was used in the wrong places.
The erroneous coloring affects only part of the main, intaglio layer. The subprint layers do not show any changes, they are printed in the correct color.
As for the main layer, the bottom of the square frame in the left margin, which should normally be brown, is also dragged in green.
A big curiosity - a rare item.