From the jQuery docs:

when calling .trigger() with an event name matches the name of a property on the object, prefixed by on (e.g. triggering click on window that has a non null onclick method), jQuery will attempt to invoke that property as a method.

When the document loads we trigger a `ContentLoad` event, which causes jQuery to execute the function called `onContentLoad` by default. In addition, we attach a listener to the document that catches the `ContentLoad` event and executes the function as well.
We need to either rename the function or remove the extra listener.