What's the issue?

When trying to use amp-analytics to track a selection in an option select using the data-vars-* attribute, I notice that the event does not get tracked by amp-analytics.

Please refer to this CodePen to see this happening.

As you can see in the CodePen example, there is an element to track the click on the which successfully triggers. But then the second element, which is concerned with tracking the actual value, never fires. You can see this on the network tab in the dev tools. Is there any better way of tracking an option select with amp-analytics that I could use instead of this method?