That's unusual, but not unheard of.
Perhaps you wrote something that particularly unnerved the essay-readers? Too much prose? Way too little? Too many first-person pronouns? Out of scope?
Free GMAT Club tests ($250 value) in addition to any other discounts or coupons when you buy the Knewton Course with KnewtonBest-GMAT-Club discount code.
Use this promo code when you sign up for Knewton: KnewtonBest-GMAT-Club