When you move a credit from one account to another using a General Journal Entry, the original account will keep its balance until you apply the credit.
To clear these balances and resolve the open invoice error, simply go to the original account, select Customers, then choose Receive Payments, and click on Apply Credits.
I also recommend checking this article for more detailed steps: Transfer Customer Credit from One Job to Another in QuickBooks Desktop.
If you have any further questions, please feel free to reach out. We're here to help you anytime.
