Inline fixed setting

Hey Guys,
I was following Josh’s video on building a Mega Menu https://www.youtube.com/watch?v=8_VsXYSlHH4

In the section about setting the width of the dropdown to 100% (around 10 minutes) he talks about the Inline Fixed setting and that when you turn it on, the dropdown should span the width of the screen 100%.

In my situation, it doesn’t quite work that way - I end up with a gap at the left edge of about 75px when I open the dropdown.

A look at the code, and I see there’s an element.style (on the dropdown)

setting that changes from inset: 31px auto auto 0px; when the Inline Fixed is NOT set. But when it is, inset IS set it changes to: 82.5px -74.2344px auto auto; This is when I see a gap on the left hand side of the dropdown. When I change the -74.2344px to 0. The dropdown spans the full width as it should.

I’ve looked through my settings to see if I have something set that I shouldn’t have but it looks like everything is setup correctly. So my question is, what might be causing the gap, what controls that 74.2344px setting, and can I change it or is the solution that I need to override it with CSS of my own?

URL: https://foamlamina1stg.wpenginepowered.com/ (Products)