Bought it on the /r/appleswap subreddit. It’s still in transit, so I don’t have it on hand yet. A Google search seems to say it means it was bought at a third party store, but that store never sent whatever information to Apple that it was sold(?). The seller provided a screenshot of a Genius Bar service receipt where they reset the Mac mini so he can sell it. I got the serial number from here and the photo of the box they provided. I put it in on Apple’s Warranty check page. Told me the purchase date isn’t validated, but the Genius Bar email says the date of purchase is July 10 2022. Nothing seems to happen when I put that date in. The email also says it’s still in warranty.
It doesn’t really matter to me if it’s in warranty or not, I’m just wondering if this is something I should be concerned about or not.