Near the end of the episode when Mary is speaking to Conde about leaving for Scotland, you can see her dangly earring tangled up in her hair in one scene, then loose, then tangled up in her hair again.
Not that it really matters much, I did notice a slight wardrobe error. After Francis and Mary meet to make an heir, Mary is seen shortly after speaking with her mother. At that time, Mary is seen with earrings that have points, that are facing inward toward the face, but shortly after while she is talking to Conde we see that the points of the earrings are now facing away from the face.