Discolouration on left side of stainless steel graphite Apple Watch series 7

Has anyone else had this discolouration on their Apple Watch? I bought the watch a few days ago, and I called up AppleCare to see what it was for. I described it verbally, and they said the stainless steel should have a uniform shininess, so the watch is defective and to send it back. Here is what it looks like. Has anyone seen this before?