Uncaught TypeError: Cannot read property 'sendMessage' of null

I just noticed this error in the console:

Uncaught TypeError: Cannot read property 'sendMessage' of null 
  (anonymous function)
  h
  e.trigger
  (anonymous function)

I’m using ember-cli and I can’t reproduce this consistently. My app works correctly and I can navigate to all the pages, but after a random number of quick clicks between different links the error appears.

Once the first error of this kind shows up, it will appear always after every page transition.

Doing a page refresh “fixes it”, the error doesn’t appear for a while.