Safari page dislodging and moving from side to side out of place

Why does my iphone safari page become dislodged and wiggle or move around so much? It’s very annoying. One second I’m scrolling down a page and the next my page is bouncing and and moving around and out of my screen dimensions.

is there a way to disable that? Why does iPhone have weird features like this? It’s so inconvenient.

example below. That black part is my page shifting around every time I scroll up and down