Select Component not binding value

Hello Everyone,

I have a problem with a behavior and I need to know if it’s a bug or if there anyway that I can be solving this because already lost an entire day with it. I made a quick demo of what’s happening but in resume is: I have states and cities related to states. When a choose state value, the select of cities change, until here is ok, problem is, when I select a city and then I select a new state (for load diferentes cities), the value how remains selected for the city on interface is a blank space but if a show the value on ng-model, shows a city which’s present into the values of the select. I don’t know why it’s not selecting the right value. Would be glad for any tip about how can I solve this :confused:

Here’s my demo in codepen: