User gets the following error when attempting to unapprove (change the Approval Status of) a document which is not Change Controlled:
There could be some hidden special characters in one or more of the property fields of the document. For example a special character in the Remark field may make Assetwise think the field value is being changed as well. Thus the error above.
You'll need to use direct table update to delete the special character from the Documents table's field/column, before using the frontend to unapproved the document.