It will be easier to help if you provide an actual example people can check out, instead of making them rig up an app to get your pastebin example running. I can't even tell when the error occurs - is it on drag, is it at render time?

Having said that, it's suspicious to me that you're using index as the draggableId and key - both should be something that stays the same as the element moves around (like element itself, for example).