This has been brought up before in #664 and a couple of other duplicates, but does not appear to be fixed: http://plnkr.co/edit/UoSC77d8cizGhBPsfYrr?p=preview
Putting ng-class on a tag with ui-view breaks the ng-class.
From #664, I'd assume that this is merged and working, yet as the plunker shows, it isn't.