I have used multiple custom fonts in my designs & I have never had an issue. I’m not sure if there is a fix or if some fonts just don’t work, but in all of my “chalkboard” themed watches, I have used a fairly basic chalkboard font. It shows up in Facer Creator & on the webpage page, however, when I sync it to my watch, it does not show up. All of the icons & colors show up correctly & the date is in a script font that shows up. My watch is a Gen 4 Fossil Venture HR.