Not sure if this is the cause, but when the first control on a view (like a button or textbox - and maybe even a scrolling region) on a page is part way down the view, Infopath scrolls to make it at the 'top' of the window.
Try putting a button, shrunk right down to a few pixels at the top left of every view, outside of the scrolling region.
When the view switches the button will get the focus and prevent Infopath scrolling down.