Would not the sanding have removed any blush if it was there?

Wet sanding will usually remove blush, but dry sanding can just push the blush chemicals around. Safer (assuming all the wood is covered with some epoxy) is to give it a good scrub with water and a Scotchbrite pad. If you use detergent in your wet sanding bucket, it's best to rinse with plain water before recoating, IMO.