O365 Patterns and Practices JavaScript Injection / Embed JavaScript

I have a vanilla O365 developer site which I'm deploying the app in the JavaScriptInjection example here - http://ift.tt/1Dhr3de

I'm getting pretty inconsistent behaviour across IE 11, Chrome and Firefox.

For example if I click on the Home link on the left navigation I (almost always) don't see the message

If I click on the browser refresh icon I (almost always) do see the message.

In Chrome, it appears to work a bit better, but still not seeing the message consistently.

I'm assuming there is something missing from the example, I've tried adding ExecuteOrDelayUntilScriptLoaded to the scenario.js file without success.

Is anyone using this example consistently, do I need to update something?