Engage "Next" button disappears

I am working with the "Labeled Graphic" in Engage. I have created all of my labels on the picture. However, when the user has clicked on the last label, the "Next" button disappears. All player settings are correct (and interaction properties). I think this is a product error that needs to be fixed.

The learner needs to be able to advance to the next slide and is not able to do this without the Next button. As the attachment shows, the Next button is grayed out but the Previous button is not.