Ok, it's a little convoluted, but this worked for me. I had two items on my wishlist for the longest time. When I mouse over the items, some options appear at the bottom of their thumbnail. One of those is "Add to wishlist". You wouldn't think to press that because it's already in the wishlist supposedly. However, if you press it, you will get a message it's added to wishlist. Now when you mouse over, it will show "remove from wishlist" button. Press that, and it will be removed. Now you have to refresh the wishlist page and it should be gone.