I edited a form to add a new metadata block between two existing metadata blocks. In the form builder it appears as though the order I specified is accepted, but when I upload the form to the server the new MD block displays at the bottom of the form.
This particular issue was the result of a form corrupted by a previous bug. The bug was fixed already, but the diagram and the model in this form had become out of sync. Under normal circumstances the order of the shapes in the diagram is the same as the order of the elements within the model. After repairing the form XML I was able to reorder metadata blocks without problems.