ng-class not updating outside the html

I have used following code in my project. Sorry I won't be able to share any plunker or jsfiddle

<div class="container {{!model.showHeaderBasedError}} full-height" 
ng-class="!model.showHeaderBasedError" 
data-ui-view="main_container"></div>{{!model.showHeaderBasedError}}

As the output state: the variable used outside the html is working perfectly fine but the one used in the Html is not updating.