The mark (there is just one) is perpendicular to the feed path of the printer, not parallel. It's almost like a scuff mark about 1/3 of the way up the page.
Head strike maybe? I have them rather at the end of the sheet with my R1800 and IGFS.Raising the head ("thick paper" adjustment) does cure most (if not any) of it.IGFS has a strong tendancy to curl under ink, water or other coatings...
I don't think it's a head strike as there is no smearing of the ink and no ink marks.Neil
May not be a head strike per say ... what is probably happening is some part of the head mechanism itself is slightly rubbing the surface of the print for 2or 3 passes. You should be able to watch the paper feeding, knowing from a previous print where the rubbing will occur and watch the ends of the paper at that point ... are they releasing from a guide? Perhaps the leading edge sticks on a guide briefly and bows the paper briefly.