Hi, which version of Libsass are you using?
It seems to work on http://sassmeister.com/.

Disclaimer: I don't exactly know what I'm doing, but I'll give you what I know:
I use the libsass version of Foundation, as described on http://foundation.zurb.com/docs/sass.html (under "Creating a Libsass project").

This is what I can see about versions:
node-sass@0.9.6 node_modules/node-sass ├── node-watch@0.3.4 ├── object-assign@1.0.0 ├── get-stdin@3.0.2 ├── node-sass-middleware@0.3.1 ├── nan@1.3.0 ├── shelljs@0.3.0 ├── yargs@1.3.3 ├── chalk@0.5.1 (ansi-styles@1.1.0, supports-color@0.2.0, escape-string-regexp@1.0.3, strip-ansi@0.3.0, has-ansi@0.1.0) ├── mkdirp@0.5.1 (minimist@0.0.8) ├── mocha@1.21.5 (diff@1.0.8, growl@1.8.1, commander@2.3.0, escape-string-regexp@1.0.2, mkdirp@0.5.0, glob@3.2.3, jade@0.26.3, debug@2.0.0) └── sinon@1.10.3 (util@0.10.3, formatio@1.0.2)
And this is the error notification:
Running "sass:dist" (sass) task Warning: /(path):(line number): error: error reading values after $height Use --force to continue.

The "values after $height" changes when I delete the "!global" 's but then another errors occur. I understand that "!global' is deprecated in newer Sass versions, this might have to do with it?

Hope this helps.

Sorry for the late reaction, I'm on holiday right now. I'm going to look into this further, but for now, maybe issue #3 can help. Also thanks for the details with the versions.

Try updating grunt-sass to version 1.0.0 (foundation/foundation-libsass-template#23)

I'm using grunt-sass 1.1.0. The bug with !global is unfortunately not resolved :)

Hmm, could you send me your grunt file?

Do you need the complete gruntfile.js or only the package.json?

Could you give me both? And maybe also the sass code where you use the mixin. I just tried it with grunt-sass 1.1.0 and everything works in my case.

I'll close this issue for now.