Usually a wood color variation is either typical of the species (such as with hickory) or an indication of grade. Common grade usually shows more grain and coloration than Select. I don't think you should consider this a defect - it is a matter of taste. If the store sample did not reflect this variation, one could feel misled. Our Home Depot sample of the natural maple in the Vanguard TapTight line does show variation in color, which would be fine with me. What would not be fine is the variation in height of individual boards, which seems to be commented on alot!