When you open the horizontal scrolling demo in portrait mode then rotate your iPhone by 90 degrees into landscape mode and back again, the position where the scrolling stops is too far to the right.
A similar problem appears when you open the demo while in landscape mode and then go to portrait mode.
The table scrolling demo works fine in both cases.
This issue seems to occur when you "resize" the browser window wich happens on landscape / portrait mode changes. If you an event listener (e.g. window.onresize) you can reload the page(s), but then you loose the page you're on.