str.split is nto a function

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This is a (check one box):

- [ x ] Bug Report
- [ ] Feature Request
- [ ] General Query

My version of UI-Router is: (type version) 1.0.30

# Bug Report

#### Current Behavior:

i am not sure why this is getting thrown in random places:

```
angular.js:15544 TypeError: str.split is not a function
at splitClasses (stateDirectives.ts:685:47)
at Array.map ()
at getClasses (stateDirectives.ts:689:18)
at update (stateDirectives.ts:692:32)
at processQueue (angular.js:17922:37)
at angular.js:17970:27
at Scope.$digest (angular.js:19089:15)
at Scope.$apply (angular.js:19477:24)
at done (angular.js:13320:47)
at completeRequest (angular.js:13577:7) 'Possibly unhandled rejection: {}'
```

Is there something that i am missing. We were on a very old beta 1 release of ui-router that never gave us 1 issue. Upon upgrade we started getting these errors on the console, BUT everything seems to still work as designed.

Has anyone every seen this?

# General Query

Please direct general implementation questions to StackOverflow:
http://stackoverflow.com/questions/ask?tags=angularjs,angular-ui-router

Please review the Sample Application which highlights common approaches:
https://github.com/ui-router/sample-app-angularjs

- [ ] I have already asked my question on StackOverflow and nobody could answer the question

- [ ] I have already reviewed the sample application for examples of common approaches

- [ x] I believe my question can only be answered by the UI-Router maintainers

(type general query here)