Flickering div navigating through pages

i have a jekyll site on github pages https://myartportfolio.github.io/paper/paper-2

ON CHROME: clicking through the links on the navigation results in the the navigation disappearing while the page loads. (firefox:no issue, localhost: no issue)
ive tried reordering the css load order but cannot figure out what is causing this?

Any help would be greatly appreciated!!

looks good to me, did you do anything to it?

might just be a cache thing. If the html pages are not cached at all then when the page loads it does a refresh and you may see it like you describe. GH may have some cache things it does to help with that.