@CoullPert
UmmÖ I have only spoken with them
Any submission format, other than .txt avoids this issue. .docx, .odt, .html and even pasting your text into the form avoids this.
Usually, those are Mac encoded characters that are treated as windows ones.
A couple of months ago I made a change in the processing flow that detects these characters. Is that text from recently, or from text posted long ago?
One puzzling thing though, from every test I've ever conducted with LibreOffice, if you do a 'Save As...' and select .txt, the resulting file is usually encoded in UTF-8 with BOM, and such a file won't have miscoding and won't be mis-processed by our software.