yeah.. not sure what it is, but I'm not going to try to figure out why. it's strange - sometimes it would work, and sometimes it wouldn't. so, one time I restarted gulp, and all of a sudden it broke again.
so, I had another strange issue: http://i.imgur.com/8MUwFpf.png -- my icons are horribly off-center. I'm not using md-icon (couldn't get it to work) so I'm using ng-md-icon instead, if that makes a difference.