Ember bind controller attribute to hbs template

In my Ember template/hbs, I have the following code;

Also in my backing controller js, after some AJAX processing, I do

self.set('myPanels', myPanels);

Now for some reasons, it seems that the controller attribute which I am setting is not getting tied to the hbs file

The only thing is the attribute is not available instantly and I have to do some AJAX processing to set the data & at the end of that, I am setting myPanels

Am I doing something wrong ?