This certainly ain't standard - I lived in the states until about a year ago, iirc Carl's Jr was the only one that served non-breakfast during "breakfast hours". Even at McDonald's in Hong Kong or mainland china has a breakfast hour thing where you can't get burgers or nugs during breakfast. I think the other fast food chains do it differently but I've stopped eating fast food since it's more expensive than local stuff anyway. Hell, certain places I like don't serve anything but youtiao and soy milk in the morning when I really just want some basic rice & whatnot

Idk maybe I'm just in the wrong corner of Asia lol