I have seen some discoloration on edges that re cut before exposing and processing, especially when toned, though can't explain why. Yes all paper is cut at the factory, and maybe my trimmer's blade was dull and therefore made some rougher cuts that allowed it to happen. Haven't seen it a lot, but enough over the years to remember. I have also noticed excessive swelling sometimes on those cut edges, and it dries with a little rougher that normal. To avoid this I cut when dry.
Your results may vary.