I opened today a PDF created with pdfsharp 1.31x (ancient version) and the output was totally weird. All textframes were rotated by 180°, had spaces after every character, but were readable due to the fact, that horizontal scale and font size were negative. See image. Opening in Acrobat or Illustrator everything is fine. To get a normal PDF I have to save the file with Illustrator. I guess this is a problem caused by pdfsharp and not an Affinity problem, just wanted to show how software can create PDF.