Ordering list produces duplicates

Using Safari on OSX, when I try to move filters up or down after page reload i see two of that filter.

This seems to apply to any filter that I try to move up or down.

I have just tried this in Chrome and I'm seeing the same thing - when you click Up on the last filter in the list, say, the page reloads and you now have one more filter in your list, and there is now two of that particular filter.