I recognize your concern regarding the Vendor A/P Summary Report showing a bill that has already been paid, JIT. It can be challenging when transactional details don't align correctly in reports.

In QuickBooks Desktop (QBDT), paid bills will not appear on the Vendor A/P Summary report when accrual transactions such as bills or invoices are settled. If they do, it's likely because QuickBooks doesn't recognize that the transactions have been paid due to:

• Unapplied bill credits or payments
• Unapplied credit memos or payments for invoices

The following may also cause paid transactions to appear on the open transactions report:

• Incorrect aging report preferences
• Incorrect terms are set for bills or setup issues in the Terms List
• Incorrect dates on the server or workstation
• Bill payments are dated after the report's date range
• Potential damage to one or both transactions or their linking

To resolve this, we can unapply bill credits or payments and reverse the process. Here's how:

1. Go to the Reports menu.
2. Hover over Vendors & Payables, then Unpaid Bills Detail.
3. Find the transaction with negative amounts indicating unlinked bill credits or bill payments.
4. From the Vendors menu, choose Pay Bills to apply bill credits and bill payments.
5. Please know that matching transactions must have the same A/P account.

If the issue persists, I suggest checking your Aging Report preferences if the Age from due date or Age from transaction date are selected. I'll guide you on how to do it.

1. Go to the Edit menu and select Preferences.
2. Select Reports & Graphs and tap the Company Preferences tab.
3. Check your aging reports preference:
   • If the Age from due date is selected, a transaction is "current" until the Due Date, and then the aging begins.
   • If the Age from transaction date is selected, the aging starts immediately on the transaction date.
4. Hit OK.

For additional details and alternative solutions, refer to this link: A paid bill or invoice appearing on the open transactions report or window.

Additionally, check out this page to learn more about paying bills. It provides an overview of how to apply any credits you want to use towards bills.

Moreover, visit this article about handling different data in QuickBooks: Understand reports. It covers basic information about the reports.

Let me know if you have further questions or other concerns about paid bills or reports in QuickBooks. I’ll be right here to assist further.