PDF Generation bugged

Production environment with the latest version of Frappe/ERPNext.
ERPNext: v12.4.3 (version-12)
Frappe Framework: v12.2.1 (version-12)

When I want to generate a PDF from any document, e.g. sales invoice the PDF is totally messed up.
The HTML preview looks fine and printing the HTML Version works, too. But PDF generation has an issue.

This is how it looks in the desk as HTML preview

This is how the PDF looks like

Sorry, already asked and solved in this post.