ExecuteOrDelayUntilScriptLoaded not executing after page publish

In SharePoint 2013 I have a page that is using the Script Editor web part.
In the script editor web part I have the following:

ExecuteOrDelayUntilScriptLoaded(startIt, "sp.js");

function startIt() { alert('Started'); }

How come the alert is called when the page is unpublished, but once I publish the page then ExecuteOrDelayUntilScriptLoaded() is not firing. I'm using IE.

Is this a possible bug?

Thanks