Fonts buggy in XD Windows.
I use a font manager to install fonts (Extensis Suitcase). I have read XD might have a problem with font managers. I will stop using XD before I bother manually installing fonts into my fonts directory.
When I open an Illustrator file some installed fonts are reported missing in XD. Fonts not reported missing are showing correctly but the font is not in the fonts dropdown menu.
For example I have a font on my system (not Adobe CC font) Proxima Nova. This has the full range of weights. In the Illustrator file fonts are showing as they should. When I open the file in XD most weights of this font are showing but "Light" is missing (for some reason) When I try to replace the missing font the replacement dropdown is greyed out

The fonts that have imported and are showing as they should get the full range of options in the Character pane:

BUT
If I want to use "Proxima Nova" somewhere else that font is missing from the menu:

