What exactly does the package showhyphens tell us about hyphenation points? According to its documentation, it "will show all possible hyphenation points".
But when the word contains a ligature, it will not only fail to tell us that there's a hyphenation point between the two characters of the ligature (presumably because the ligature is a single glyph in the .pdf), but it will also erroneously report that there's a hyphenation point elsewhere in the word that's not actually there.
Is there any way to get showhyphens to report the actual hyphenation breaks in words with ligatures?
\documentclass{article}
\usepackage{showhyphens}
\begin{document}
office \parbox{0pt}{\hspace{0pt}office}
\end{document}
