HELP! Presenter Next Button

Hi All - I'm stumped! I could really use some help so I hope someone somewhere is still about and can assist me!

I have two courses I created in Presenter. They function GREAT, except for one thing... 

I'm certain that last week when I posted the courses for my client to review the standard Presenter Navigation buttons (Play/Pause, Back and Next arrows) performed like this:

Play/Pause (as expected, played and paused my course)

Back button (as expected, moved to the previous slide or the specific slide indicated in my Presenter Slide Properties for custom navigation

Next button (as expected, moved to the next slide or the specific slide indicated in my Presenter Slide Properties for customnavigation EXCEPT!!!!! when the course got to the last slide, and the learner clicked the Next button, I was certain on the last slide it closed the window. 

My course has a quiz, but AFTER the quiz is a references page so I cannot customize the button on the quiz to close the window, I need Presenter to do that (they do not want the exit button in the top corner displayed - I don't know why, I guess they don't like it.

Anyway - today I republished the course, made minor edits to timing and added a revised audio track, but they are telling me the next button on the last slide does nothing now.

Help - can anyone tell me if I can fix this for them??? Please?

Really appreciate the assitance of all you heroes!

Jacqueline