Next Button Disappears when Revisiting Previous Slide

Hello,

I have a few slides throughout my project where the Next button is disabled until all of the ovals on a slide are marked as "visited". This function works great if someone is going through the course in a linear fashion.

But, when the Previous button is clicked to view the Previous slide, the Next button on the originating slide is disabled even though all of the ovals are showing the "visited" state. 

There are no questions on these slides, only informational layers. 

Is there a special trigger I need to input to allow people to revisit previous slides?

I am using Storyline 360.

Thanks so much in advance!