DNA should flash off quickly, but it still might take a couple minutes, especially if it was really soaked instead of just on surface.
DNA is not a standard product. The de-natured means they put something in it so it would be unfit for human consumption. Different brands use different additives. I have only reard of this being a possible issue once. Someone didn't close DNA completely, most of it evaporated used what was left on flatwork. Poly finish was a mess. The assumption being the alcohol flashed off with the lid loose and the concentrated toxin caused problems. Seems a bit of a stretch to me, but I have found if I switch my loose change from my right pocket to my left when using steel wool between coats I get better finish results....
THere are so many variables in most shops it is hard to figure it out. Hope someone here has a better idea than I did.