I discovered this back in January 2021 and reported it, and while some is part fixed, it is still possible to make a mistake for one scenario....

If you open an expense (either matched to a bank feed transaction or not), QuickBooks will pull up on the left all open bills and credits on the right hand side for that supplier. Great for matching outstanding bills to those bank feed transactions recorded as an expense instead of matching to a bill (either missed or bill received late)

Open the expense and match a bill previously recorded in a filed vat return to the open expense = works

Open the expense and match a bill in the same vat period as the expense = works

Open the expense and match a bill to an expense recorded in a previous vat return fails, as it creates an expense exception payment for this value on the vat return, duplicating the expense.

You should also note you cannot go back into the expense to amend as it will disappear, you will need to contact QuickBooks for support for a solution.

Test it this out in the sample company.

So although matching up expenses to bills seems to be an option, be very careful. If you are unsure, un-match the expense and add the payment to the bill in the correct QuickBooks method.