A Tricky Header

[Billyjeanplxiv]

I have a tricky pickle.

I was handed the workings of a site built out and the header works great on everything but the homepage.

So I built a new page out, header works fine. I decided to rebuild the homepage thinking that would fix the header. It didnt.
The header's background disappears on everything but the homepage.

I've checked everything I know how to check to see what is making it do this.
I even rebuilt the header. I was passed this project to finish up and this error is kinda holding me up.

The image attached is what's going on. Left is the error, Right-side is what it should look like.
I've changed themes, I've checked every column for funk, the header is applied on every page.
If you could assist me that would be great, otherwise, I'm stumped.

I'll be able to provide more details if you need them. This isnt the first site I've worked on and i'm used to encountering issues but this one has me wondering whats up.