[Hummingbird] Hummingbird and Divi theme caching problem

I've experienced a issue on two sites concerning Hummingbird on sites with the Divi theme.

Repeatidly the site will stops loading the style.css from the child theme.

If I clear cache, all returns to normal but that never lasts. I disabled the cache on the andisondesign.com website a while back and the issue has not happened since.