We've been using inskscape to design metal artwork for several years on a MAC Pro (still using OS Mojave V10.14.6 and Inkscape V 0.91.  May be outdated but it is stable and still allows the save as cairo png function which is useful for us.  We are moving back to a PC platform (Windows 10 Pro 10.0.19042 build 19042) and running the latest Inkscape V1.0.2-2 (e86c870879, 2021-01-15).

We have a long list of fonts that we use on the mac (mix of TTF, and OTF fonts as well as the native MAC fonts) which we also need to now use on the PC.  Copied over the library of TTF and OTF fonts and installed them for all users.  No problem - the font names all show in Inkcapes font menu.  The problem is that some which work perfectly on the MAC show up in the PC Inscape font menu with a series of "squares" behind the font name rather than a sample of the font.  If you try to apply that font to a text string in a text box, the text disappears). 

 If we open work or any other program on the PC, the same font shows in the menu (ex. MS Word) and applies perfectly to any text.  So the problem appears to be with inkscape.  Here are two very standard fonts that are a problem  - Serpentine Medium and Serpentine Medium Oblique.  Both are OTF fonts for windows ands MAC.

Why do these work in the MAC version and not the windows version?  Also, after removing some fonts from windows, there are black spaces in the Inkscape font listing that won't go away.  This did not happen in earlier versions.  I also believe that these same fonts worked fine in the Inkscape windows versions prior to release of 1.0...

Help appreciated!