You’re making a PDF about weird file formats and PDF… and the PDF doesn’t let you write “file”… very meta.
@Ange knowing extremely little about PDF, my guess would be some encoding issue related to the fact that there's probably a "fi" ligature glyph in that font, since it also happens to "first". Am I close?
@saua That sounds correct. I just don't know why it happened, and it's a funny outcome :)
@Ange
Maybe use a font that has the fi ligature?