Thanks for getting back to us, jerrym.

I have additional troubleshooting steps that usually resolves this.

Let's find any adjustments associated with multiple serial numbers. Follow these steps to pull up the Custom Transaction Detail report:

1. Go to Reports.
2. Hover your mouse to Custom Reports and select Transaction Detail.
3. In the Display tab, set the date to All.
4. From the Filters tab, search for Transaction Type.
5. From the Transaction Type drop down, choose Inventory Adjustment.
6. Click on OK.

For your visual reference, I've attached some screenshots.

Then, click on each inventory adjustment and make some changes. But before you do so, I recommend you reaching out to your accountant.

The following article will walk you through activating the Lot Number feature in QuickBooks Desktop: Use Serial or Lot Numbers.

Please let me know how it goes by leaving a comment below. I'll keep an eye to your response and help you further.