Fonts Randomly Not Working

For the last few weeks i've been having a problem where a seemingly completely random selection of fonts just won't work in Corel. These are 'not installed' fonts in a location that is monitored by Font Manager. The fonts show fine in Font Manager, and in the font list in CorelDraw. They even preview correctly at the bottom of the font list. However, when chosen, the text jumps back to arial. There seems to be no consistency in the type of font, and sometimes some members of a font family work and others don't.

Just to clarify how we are set up, we use OneDrive to synchronise fonts between all users here. We have a folder called Active Fonts on each computer which is synchronised by Onedrive. When someone uses a new font, they add the font to this drive and Onedrive then updates the local folder on everyones computer. It avoids having thousands of fonts on a network drive which really slowed things down, keeps the fonts the same for all users, and has been working perfectly for a few years now. 

I've made a little video showing this behaviour. As you can see, the majority of fonts are wokring fine, but a significant number just revert to Arial, and there doesn't seem to be any logical reason. The video is at:

https://vimeo.com/640302962

I've tried repairing Corel, uninstalling and reinstalling Corel, resetting the font database, but nothing helps. Any ideas what is going on here?