I have seen this with the multi- company GL enhancement installed. When the user sets up a new main account in company 1 it asks you want to set it up in company 2. If the user says yes it writes the main account and 3 digit company code from company 1 to company 2 ( instead of writing company 2's 3 digit company code). So when you consolidate them you have the main account and 3 digit company code from company 1 and the main account and 3 digit company code (of company 1) from company 2, making a duplicate row when the designer runs. To fix it, I went into DFDM and changed all the incorrect 3 digit company codes in the GL data to the correct company code for the data set.