David;
Something changed and it appears it was not the reels. Yes, bubbles and contaminants in the water can do this. You say distilled water but let me give you a story.
I was in Montana giving a workshop and nothing worked the first day. I tried everything and it just would not work. The coatings were awful, but the emulsion was ok.
It turned out that the lab was used the week before by Sandy King for carbon printing, and the tiny amount of oil in the carbon glop had gotten onto some of the trays in the sink. Even though we used DW for everything that tiny oily residue did us in! So, we washed every piece of equipment with soap and water and the problem went away, but still we had a tiny hint. If we went into other areas and picked up some residue in other labs, enough stuck to our fingers to cause blemishes.
Who knew? I should have but didn't suspect it and Sandy and his class had left the lab sparkling clean to all appeances. It was probably just a drop or two.
I had the same problem in my lab here for 2 weeks. I could not coat anything and suddenly the problem vanished. This was about a year ago. I've never had it again, and hope I never do. Some mysteries cannot be solved. I would guess though that a good lab cleanup of everything with detergent and then with hot water might move things in the right direction.
Good luck.
PE