When executing a Data Exchange, the following error is displayed in the GUI: "Cannot exchange sheet <sheetname> duplicate column name '<columnname>' on index 3 and 4"
There is an ID mismatch between the columns in the source and target data sources that are being exchanged. The IDs of the columns are visible in the REST API definition of each workbook.
An enhancement request has been filed to improve the matching criteria.
To work-around this issue, use the REST API to export the target data. Then edit the JSON data to ensure that the columnIDs precisely match the source data.