Cannot scroll past specific point in doc

[sunriver]

This is in a Word 2013 on Win 7 (64).



In a 75 page document (pages are irrelevant, just wanted to indicate a moderate sized doc), when in a two page view to edit, scrolling with the up arrow continually pressed or clicking in the scroll bar, the document location will jump back to a specific position. Turning on the hidden characters reveals nothing that I can see. When in one or three page view this behavior does not happen.

Clicking on the scroll bar button (keeping it held down) and moving the scroll button up past the trouble spot will get me to an earlier position in the document.

Smart scrolling has been enabled and disabled - neither make a difference.

Converting to Word 2003 format lessens the behavior in that I can scroll up past the location however the screen still jumps and is not behaviorally in sync with the rest of the document while scrolling.

Looking for help to correct this oddity.

Thank you in advance for anyone's assistance!