When Zooming in or out, lines appear in the image

Today, when zooming in to inspect a newly scanned image, lines first appeared in the upper left corner, which caused me to first believe that the scan was bad. The thin lines had the appearance of missing data. When I changed the zoom, the number of lines increased, When closing the file the lines disappeared. I opened a previously scanned and retouched file and the same effect occurred when zooming. However, when closing the file, no question apppeared regarding saving changes, so I suspect only the screen image is somehow being corrupted.

Has anyone had this experience and how did you resolve it?

I think what you are referring to is a mismatch between the lines of pixels in the scan and the screen pixels....it is common good practice to look at scans at 50% or 100% view.