Do not use steel wool on stainless (especially the cheapo stuff used by Weber and others). It will leave small particles behind that will leave little pinpoints of rust all over the grill. I believe it's just leftover oils from manufacturing. Use a good solvent (NOT mineral spirits unless you follow up with something else) and wipe it down well. Lacquer thinner works best. It cuts through and dries clean. Mineral spirits is just Kerosene that knows somebody and leaves oily residue. Don't bother with rubbing alcohol either. Too much water in it. Denatured alcohol would work well too. You could also use a green scotchbrite pad but you do risk deeply scratching the surface. Use that only as last resort
That is honestly what I thought when I looked at the picture. Seems like a protective film that needs to be peeled off. If not, I agree with Larry’s recommendations for cleaning. I need to checkout lacquer thinner.
Yes, the "wrinkle" is an optical illusion. The straight line that goes up, around the thermometer and back down is where the film used to be. I'd be more inclined to think the little lines were related to the film if they weren't under the thermometer where there wasn't any film. They appeared after firing up the grill the first time.
Peter, that sounds like a defect. I would be on the phone with C/S. They will likely ask you to email them some photos and I expect they will have a new lid out the next day. Just keep the old one for a spare if they do send you a new one.