Hi @elliot,
I just wanted to let you know that I’ve discovered that, in creating a new Field Group today the drag and drop re-order is working. It’s just on the one that was created before the update that it doesn’t work!
It’s also not really a huge issue for me anymore – I’ve got things in the order that I need them to be. But I will keep working with you to help find a solution to this error if you would like.