Either the is a missing starting date (maybe because of the two different ones it was forgotten to be added when this sentence was added) or it should say ‘until’ instead of ‘since’.
This note was printed starting 01.07.1985, first issued on the 20.06.1986 or 20.10.1986 (there seem to be multiple sources saying different things in Wikipedia), withdrawn on the 20.04.1998 and devalued since 20.04.2018.