$cordovaInAppBrowser:exit works multiple time when state changes

Hi there. I’m using ngCordova InAppBrowser. I’m using on exit like this:

$rootScope.$on('$cordovaInAppBrowser:exit', function(e, event){
	alert('exit!!!');
});

At first time it works fine. But when go to another state and came back, it works one more time in every state changes. This happen on both android and ios.

Any idea?