Saw had similar issue with our long gone 3800.
Some papers will swell unevenly under heavy ink load, develop a waveform like shape (when viewed edge-on from feed exit) and the peaks of those waveforms will contact PW, or after I removed the pizza wheels, contact plastic bits on the roof of the feed area.
Shots with heavy black areas were the worst. None of the home remedies ever worked.
That said, the 3800 didn't have vacuum hold-down.
Also, those marks don't look like typical PW boo-boos. PW marks tend to be very small pinpoint marks of uniform size, of uniform spacing in a very, very straight line.
These look like possibly intermittent contact with some plastic on the roof of feed area after inking either removing ink, or something knocking-off paper particles that were already inked and laying on the paper surface.
If using the same paper since Day 1, room humidity not suddenly doing anything funky, and printer otherwise working fine and now suddenly an issue, it might be 'paper dust', etc., buildup and a good cleaning in the feed area - rollers, vacuum ports etc would clear it up. That or maybe an off-spec roll of paper? If the 4100 has brushes in intake path to pre-dust paper before inking, maybe check them?
I look fwd to the day when we no longer have printing tech based on spraying droplets of ink across a narrow gap onto paper transported across sharp plastic by other bits of spinning plastic.