This is not a new thing just getting really annoying here lately. We load all fonts to the windows directory. We also have a "Font Swap directory on our network. That way if a designer needs to pull up something designed by someone else and the font is missing font manager can load it as long as that person has their font manager set to look there. Anyway, on any given day we can pull up a file we were working on the previous day and the font is missing and also missing from the network directory. Today I begin a new doc and begin to design some parking signs. I try to choose the font we've used for years and the whole font family is gone. I can see them all in FM but can't install them from there due to a recent network rebuild (network problem with permissions os some thing). I have to copy them to the desktop them install them then delete them from the desktop to uncutter.
Aside from networking issues, CorelDRAW 2020 definitely does have internal problems at showing all fonts installed on the computer's local hard disc. I have to keep version 2018 running on my computer due to the fonts that come up missing in version 2020. They're all present in the 2020 Font Manager and Windows Fonts Folder, but not in the CDR 2020 application itself.
Here's a strange occurrence too. Maybe it's my misunderstanding of the whole embedding of fonts thing. I open a file I created a few days earlier and I go to copy & paste some of the text within that file. I get the pop-up message saying the font is missing and see that it can be installed via font manager. I click yes/ok but then the font still shows as an embedded font. I then copy and paste it. That text doesn't show as being embedded. Delete the embedded version and replace with the newly created.