Do any of the fields slide?
If not, make sure that no part, not even one pixel of the vertical line crosses or touches the boundary line between header and body. If you need the line in the header, create a second line in the header and align it with the first so that it looks like one line.
Thank you - that was it! The line needed to be in the Body only; it doesn't matter if it's in the footer or not, but it cannot touch inside the Header. Thanks again.