Vendor prefixes all defaulting to webkit

[OliverJAsh]

Here is how my SCSS is compiling:

@-moz-keyframes fadeInDown {
    /* line 2, /Users/Oliver/Dropbox/Sites/oliverash.me/sass/_fadeInDown.scss */
    0% {
        opacity: 0;
        -webkit-transform: translateY(-20px);
        transform: translateY(-20px);
    }

    /* line 6, /Users/Oliver/Dropbox/Sites/oliverash.me/sass/_fadeInDown.scss */
    100% {
        opacity: 1;
        -webkit-transform: translateY(0);
        transform: translateY(0);
    }
}

Keyframes are being generated for each vendor, however the vendor prefix on the CSS transform is for some reason sticking to -webkit.