Dollar sign plus one character does not show in Code Block

[MareikeE]

I am trying to add a Code Block to my Confluence page with just "$1" as content. The content completely disappears in the Preview or when publishing the page. As soon as there are two characters following the dollar sign, it works fine, a character on the previous or following line, it works fine. It's just the combination of dollar sign and one immediately following character that does not work.

Spaces or line breaks before or after don't solve the problem.