I misspoke.
Changing the dpi does result in the line breaks moving; if I attempt to ViewCapturetoFile at the full size of 6x4m @ 300dpi, no file is created; the program behaves as if nothing happened. I tried knocking it down to 3x2m @ 300dpi and worked, but the line breaks were back. They moved around on the page, so the horizontal breaks are gone, but the verticals are still there 
