This scenario was commonly referred to as "screen drift" or "screen malfunction." This situation was usually caused by a software problem on the iPad. You can try to restart the iPad to clear the browser's buffer and data or try to re-install the browser. If the problem still exists, you can try to set the browser's buffer option to maximize the browser's usage. If the problem still exists, you can try contacting Apple or the browser manufacturer for support. They might provide solutions to repair software or replace equipment. If the screen drift problem continues, you may need to contact professional maintenance personnel for a better solution.