Font family (fonts-vollkorn) appearing as multiple fonts in LibreOffice

In LibreOffice (at least writer and calc), Vollkorn appears in the font list as "Vollkorn Regular", "Vollkorn Bold", etc.
If "Vollkorn Regular" is selected as the font, then made bold/italic, it uses a faux bold/italic, instead of the proper font version.

That's the basic problem - here's some additional info:

The font works as expected (appears as "Vollkorn", uses e.g. Vollkorn-Bold when made bold) in other applications, such as Inkscape. The files also appears as expected (e.g. Name: Vollkorn, Style: Regular) in Font Viewer.

This problem does not occur in LibreOffice with other true type fonts (eg. Liberation Serif and many others)

Manually entering "Vollkorn" as the font name in LibreOffice makes the font work as expected when made bold and/or italic, but the basic font does not show correctly (it shows as a default sans-serif font instead). This makes me think something might be wrong with Vollkorn-Regular.ttf specifically?

This occurs whether I install the fonts-vollkorn package, or download it from elsewhere (e.g. google fonts) and install it using Font Viewer, or by manually putting it in my .fonts folder or usr/share/fonts.

Very baffled. Thanks in advance!