Model Not Bound to Table Correctly

I have a sap.ui.table.Table created in XML view. Using the controller I have bound an XML model to the table using setModel.

I have modified the column swapping functionality a bit so that when a user swaps the columns, the updated positions are sent to the server which returns the updated XML with the new ordering.

I then set the updated model on the table using setModel. The column ordering gets messed up when I do this. However, when I refresh the application (press F5), the table ordering is perfect.

Can anyone tell me where I am going wrong?