loaded font can't be unloaded

I started MainType and there is a loaded font “Loki Cola” in the active list. This font is not found in Windows/Fonts. I tried to unload or uninstall it, it didn’t work - the font remains on the Active list.

Error message when I tried to uninstall it:
Failed to uninstall the font.

Error message when I tried to unload it:
Failed to unload because the font file is unknown.

Why is a unknown font was loaded when MainType is started?

Thanks

Most likely some other software that has been started during this session has loaded the font.

Does it always show up immediately after a reboot?