Issue with iPad NavBar in Portrait

So this site works beautifully on nearly all devices, but somehow the NavBar displays some erratic behaviour on an iPad Pro 11 in Portrait mode (iOS 14.3):
The Homepage has a weirdly resized Desktop-Navbar (photos below), however, both other pages have the regular hamburger style-navbar (and it’s a bloody symbol so it should be the same on all pages, shouldn’t it?).
Is Safari the problem here? Because, weirdly, after turning off “request desktop site” in the settings it displayed a properly resized Icon, but still a Desktop NavBar when loading the homepage and a hamburger-NavBar on the other pages. I really don’t get it and would appreciate some help