Wrong year of issue

How can this Notgeld be issued in 1922 if on it is stamped that it loses its validity by 31/12/1921?

The vast majority of these set pieces are just colorful paper never used as money or intended to circulate (you often find them in UNC) with nothing backing them, often issued after they “expired”. Maybe this is the case for this one too and if you ask me they have nothing to do with money and shouldn't be listed under money.

Well, everyone has the free opportunity too express his opinion, but they were not money, then I doubt so many would have been printed in war-torn Germany as Emergency Money (Notgeld).

Also Hans-Ludwig Grabowski, Manfred Mehl and Arnold Keller wouldn't write 15 tomes covering the various types, years and aspects of the German Notgeld, I think.

Nowhere have I stated that all notgeld issues were not used as money. I am talking about the very intricate, overly colorful Serienscheine (series notes) and answered why this note (if it is one of those) could have been issued void.

These were often used to fund local clubs, associations etc. and like anything that gets issued in many different styles and places people have/had a tendency to collect it and as such these authors have a financial insensitive to provide collectors a guide.
It's like today where fantasy NCLTs from sandbank issuers are taken up in coin catalogs.