Ajax is not working for Drupal comments form
I had a similar issue with ajax pagination provided by views. I was equalising the heights of the columns using javascript but it was only working on the first page. Any columns loaded via ajax weren't having equal heights calculated. The solution to my problem was to stop using jQuery's once plugin in my behaviour. This was making it execute only once but I needed it to execute infinitely.

Usually a behaviour looks like this:

Drupal.behaviors.ajax = {
    attach: function(context, settings) {
      $('.your-target-element', context).once('ajax', function(){
       var $this = $(this); 
       // do stuff with $this
      });
    }
  }


But you want to drop the once plugin like this: 

Drupal.behaviors.ajax = {
    attach: function(context, settings) {
       // do stuff
    }
  }