Recently I have the problem, that Hummingbird keeps changing the font on my website. Whenever I run a performance test or clear the cache, the font is changed to some default font. To make it load the correct font, I just have to deactivate Humminbird, and it looks the way it should. However, after activating Hummingbird again and clearing cache or running the performance test, it's gone wrong again.
After having made experiments on my test site, the problems consists even after deactivating all plugins apart from the one crucial to the theme.
I run the theme Grand photography by Theme goods.