GetMedia Not pulling Image Every Time

I have an XSLT carousel that pulls an image from a property (featuredImage) of a newsArticle document type. Sometimes I am noticing, that I get the “Hello World” image instead. What could be causing this? Here is my xslt that gets the image from the Media Library:

<img src="/ImageGen.ashx?image={umbraco.library:GetMedia(featuredImage, 1)/umbracoFile}&amp;height=325" />

This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/74442-getmedia-not-pulling-image-every-time