White Old Navy summer sundress

Old Navy white sundress with front buttons, hidden side zipper, and back elastic waist. The skirt portion (below the waist) is lined. 100% cotton. There is a slight discoloration at the front waist stitching directly below the buttons. It may be my eyes or it could be part of the fabric flaw. It does not appear to be staining. Size Small Flat measurements are approximate: Pit to pit- 20” Shoulder to hem- 35” Waist - 14.5” plus stretch for back elastic.