Brand font switching to default font after publishing

Our brand fonts (druk and steradian) are applied correctly in the brand area, and look correctly applied at the design level, but for some reason after we publish our pages recently, the fonts switch the the default (Arial?) font, even though when I myself use the published link, I see it correctly with the correct fonts! I'm sure this must be a bug, as there surely shouldn't be a way that different users can see a published link in different ways? I've included screenshots of how it should look, and how others are seeing it on the published link.