I selected a bunch of ships of different classes and tried to issue the “formation” order, with the target being any ship at all. The lines were drawn between the ships, but the “OK” button was greyed out. Workaround was to select each kind of ship individually and issue the order. Not sure if “kind of ship” in this case means frigate, cruiser etc. or if it has to be the exact same design
When group-ordering ships to formate, you can select as a target one of the ships already in the group. This makes sense, as there’s no easy way to select a load of ships and then un-select one ship in the middle somewhere. However, the resultant formation of ships don’t seem to move from their starting positions, although they will fire. Workaround was to go ahead and tell the entire group to formate around a group member, then delete the order from that specific ship.