EDIT: the issue is solved. Removing turbolinks is all you need to do.
With a Rails4 application the use ember-rails 0.13.0
After some debugging we had noticed those are turbolinks causing the problem. Using backbutton triggered turbolinks which were causing strange effects with the ember.js application like reloading all javascripts and thus overriding the state of app.
Removing turbolinks done the job. Here is a useful link how to do it: http://blog.steveklabnik.com/posts/2013-06-25-removing-turbolinks-from-rails-4