The furniture retail store (unfinished) I work for just got a maple topped island from one of our wholesalers and it has several greyish spots on it. There are ten to twenty, smaller than a dime, roundish but irregular. They don't sand out. One in particular is a cluster of about 8. The top has been well sanded by the makers and these spots are somewhat faded but visible and can not be sanded any further.
I feel like I have seen this type of spot before on maple. Does this description ring a bell to anyone.