This bug comes up when using the theme editor of the webpage builder (accessed through the wand icon at the top of the webpage editor). When I try to change the font of the webpage headers to a font I have uploaded to Adobe Libraries before, the theme editor just doesn't take it. As soon as I remove focus from the font selection field, the input resets to the default theme font. This prevents me from applying a very important aspect of our branding to AE webpages.