Hi there, Collen.
We want to ensure we're providing accurate information to get around this. That said, can you tell us more about the duplicate? Which part is it, and what type of documents?
If you're referring to transactions, know that duplicate transactions occur if they were filed in the previous return and deleted. Also, it will automatically generate an exception against the current open return to correct this for you. You can view the exceptions by going to Taxes > Prepare return > View the additional column for exceptions. From here, you can click on the exception amount against the corresponding box to view the exception report, which will show the filed amount, current amount, and total difference impacting your VAT return.
In addition, you can visit these articles to help you manage VAT and add more details to your business report inside QBO:
The Community space is open 24/7 if you have any additional concerns related to QuickBooks, Collen. Feel free to visit us so we can help you out again. Have a good one.