Both. I don't recall if this is necessary to cause it to start happening, but as soon as you pinch any amount with two fingers for zooming in/out (or to scroll down to see the rest of the cut off UI), the behavior sticks around for a while.
I'm not entirely convinced that this is anything on your end, as I have run into similar issues with my sites, and all the "answers" online don't really fix it. I believe the only real solution is some combination of setting viewport, disabling certain scrolling/finger gestures*, and ensuring that the content on screen doesn't go off the page. I'm no expert though.
*: I don't recall this being absolutely necessary, and it is generally not recommended for accessibility reasons. I believe that I mostly fixed it with just setting the proper viewport meta tag and ensuring content doesn't go off the screen.
I'm not entirely convinced that this is anything on your end, as I have run into similar issues with my sites, and all the "answers" online don't really fix it. I believe the only real solution is some combination of setting viewport, disabling certain scrolling/finger gestures*, and ensuring that the content on screen doesn't go off the page. I'm no expert though.
*: I don't recall this being absolutely necessary, and it is generally not recommended for accessibility reasons. I believe that I mostly fixed it with just setting the proper viewport meta tag and ensuring content doesn't go off the screen.