Contest entry cover image doesn't update after edit Answered

Hi, I have an entry in 3 contests. After I changed the cover image and published again, the cover image in 2 of the contests updated but one of them always shows the old cover image. Does anyone know why? Is there anything on my part can be done to make it happen? Here is the contest entry and the contest that doesn't update its cover iamge: https://www.instructables.com/id/Crock-pot-cows-milk-gingurt-vs-breast-milk-gingurt/