Header Moving Randomly

HERE

I need some help figuring out an issue with a site im developing. On the homepage the header sits how I want, flush with the container.

If you click on the About page in the footer you can see it’s no longer aligned. On the top right of the header you can highlight the search box and see, it no longer stays aligned with the container.

I’ve been trying to find what’s doing this and can’t seem to find it. Any help is greatly appreciated.