Hummingbird crashes CDN

After installing Hummingbird and letting it minify my website I have encountered a peculiar error.

I´m using the Ionicons (http://ionicons.com/) for my icon font. But with hummingbird the link loading this does not work. Originally it should be a
<link rel='stylesheet' id='ionicons-css' href='//code.ionicframework.com/ionicons/2.0.1/css/ionicons.min.css?ver=1.0.0' type='text/css' media='all' /> when viewing the site source.

But with hummingbird activated I get nothing of the sort. Instead I get a minified hummingbird.css file consisting of the ionicons. And I can´t seem to find a setting to remove this from getting minified and crushed into a single style.css hummingbird edition.

What to do? Thank you for your time.