Storyline custom previous slide button

I am using the current version of Storyline.

My file has a Main Menu screen that uses pictures to jump to each section. On the master, there is a 'hamburger' style drop-down and a 'menu' text button so users can always jump sections or go back to the Main Menu screen.

In addition, I added custom 'forward' and 'back' buttons on the master so users could choose to go through the file in a linear manner. 

I originally set up all of the navigation on the master, but I found when trying to navigate through the file using the custom 'back' button (from back to front), I get some surprises that are frustrating.

When I click on the drop-down menu to jump to a section, then click the custom 'back' button (set 'jump to previous'), I end up going back the menu screen, not the immediately prior slide in the scene.

My workaround is to put the forward/backward buttons on every screen, not on the master, then add a 'jump to' trigger on each back button to go to the screen number that precedes it, i.e. 1.5 jumps to 1.4 etc.

This is time consuming and gets a bit confusing as I'm dealing with users viewing on desktops (clicks) and mobile devices (swipe).

Any suggestions as to how I can get those back buttons to work properly on the master and avoid the custom triggering?

Thanks in advance, Chuck