> Perhaps most infuriating, Word will embed any number of styles per family, but it will only display one. Meaning, if you’re using regular, italic, bold, and bold italic in your document, all four styles will be embedded. But when your recipient opens the file, only the regular will display correctly; the italic, bold, and bold italic will be Word-synthesized approximations, not the embedded fonts.
> This last limitation means that Microsoft Word has reached the exalted state where it is not compatible with itself: it is writing data into its file format that it cannot read. Worst of all, this is not a bug—it’s the intended behavior [2].
[1] — https://practicaltypography.com/how-to-embed-fonts-in-a-word...
[2] — https://learn.microsoft.com/en-us/openspecs/office_standards...