Storyline 2 - Next button disappearing

My Next button isn't functioning. I have set the Next button to Hidden state when the timeline starts and to change state to Normal when timeline ends. I have also tried setting it to Normal when timeline reaches, or when another object state changes, or when media completes. But nothing seems to help. The issue I am experiencing is that when the user clicks Next, then when on the next slide clicks Previous, the Next button on the original slide does not appear. My slide timelines are between 5 seconds to 1 minute in length, based on the length of the audio files. Next button is set to Jump to next slide when user clicks next button. I've tested changing the When Revisiting settings in the Slide Properties to Resume saved data, Reset to initial state and Automatically decide. Resetting has worked, but then the user has to sit through the entire slide once more to progress. I have also changed the Menu Options > Navigation Restrictions to Free and Restricted. I saw no difference. Any ideas? I simply want to Next button to be present when a user clicks previous. My last resort will be to create custom buttons, but I would prefer not to.