Grunt Build Incorrectly Optimizing CSS Url - css

Question

I'm using Backbone Boilerplate and I've added the bower Ratchet 2.* dependency, then I'm importing it in my styles/index.css file from it's bower origin folder:
#import "../../vendor/bower/ratchet/dist/css/ratchet.css";
This grabs the file correctly, but for some reason when compressing it's changing the url in my #font-face selector.
The original selector looks like this:
#font-face {
font-family: Ratchicons;
font-style: normal;
font-weight: normal;
src: url("app/fonts/ratchicons.eot");
src: url("app/fonts/ratchicons.eot?#iefix") format("embedded-opentype"),
url("app/fonts/ratchicons.woff") format("woff"),
url("app/fonts/ratchicons.ttf") format("truetype"),
url("app/fonts/ratchicons.svg#svgFontName") format("svg");
After running the grunt task my new optimized style.css for this selector looks like this:
#font-face {
font-family: Ratchicons; font-style: normal; font-weight: normal;
src: url("/app/img/vendor/bower/ratchet/dist/css/app/fonts/ratchicons.eot?#iefix") format("embedded-opentype"),
url("app/fonts/ratchicons.woff") format("woff"),
url("app/fonts/ratchicons.ttf") format("truetype"),
url("app/fonts/ratchicons.svg#svgFontName") format("svg");
}
(line breaks were added for display here)
You'll notice that the entire first line:
src: url("app/fonts/ratchicons.eot");
has been completely stripped out, and the next line should be:
src: url("app/fonts/ratchicons.eot?#iefix") format("embedded-opentype"),
but has become:
src: url("/app/img/vendor/bower/ratchet/dist/css/app/fonts/ratchicons.eot?#iefix") format("embedded-opentype"),
I can't understand or explain why this is happening, but I need it resolved.
I checked the styles section of my gruntfile and it looks like so:
styles: {
// Out the concatenated contents of the following styles into the below
// development file path.
"dist/styles.css": {
// Point this to where your `index.css` file is location.
src: "app/styles/index.css",
// The relative path to use for the #imports.
paths: ["app/styles"],
// Rewrite image paths during release to be relative to the `img`
// directory.
forceRelative: "/app/img/"
}
},
I'm assuming that for some reason the style optimizer is adding the forceRelative url to an original url of ../fonts/fontfile but I can't explain why or what to do.
Help appreciated.