Microsoft Word - Roman styles changing themselves to Italic styles

I have an odd behavior popping up, after the most recent Microsoft Word update (according to client).

When choosing a Roman style for a selected set of words, some styles will change to their Italic companion e.g. MyFont SemiBold will style itself as MyFont SemiBold Italic. There are a few exceptions including MyFont Regular not changing to MyFont Italic.

Nothing has changed about the software I provided, yet they’re acting differently. Is there specific style linking methods to follow in order to avoid this kind of behavior in Word? I’ve not run into it before, but know Office is a field of landmines for fonts.

Thank you!