Next Button - Enabled - Saved State

Hi,  I'm using 360. I have disabled the next button on the start of a slide.  After the learner clicks/reviews each of 3 topics (information on 3 layers) the states change to visited.  Once all three states are visited the next button is enabled. (trigger is 'change state of Next button to normal when the state of all the pictures is visited') This all works fine. 

When I advance to the next slide and then hit 'previous' the original slide is back to it's initial state (and the next button is disabled again). Even if I change the slide properties to "resume save state" or "automatically decide" the next button is still disabled.  

Any suggestions on how to get the next button enabled when revisiting the slide without creating a variable on each slide?  (Update - I tried using a variable and the next button still does not enable when revisiting the slide - I have the slide properties set to 'resume saved state').