Resume Saved State

When a user revisits a slide that is set to "Resume saved state," the slide's timeline continues from the wherever it was when the user left the slide. If the timeline ended, then there's nothing left to play.

Alas, in your project, Storyline isn't recognizing that the full timeline ended. Instead, it sees the 4th cue point (when the layer opens) as the spot for resuming. 

In other words, this seems like "unexpected behavior" (aka, a bug). I suggest you submit the case to the staff.

In the meantime, try putting the Backpack Explanation on a separate slide. Then, when it jumps back to the basecamp slide, that slide should continue to the end of the timeline. And, hopefully, Storyline will realize that the timeline has ended when it returns from one of the scenes. 

If that doesn't work, then divide the basecamp slide in two, so the program would start with 3 slides: basecamp intro > backpack explanation > basecamp hub.