Thanks for providing a screenshot and adding clarification, @safoglio. I know some cause by the disappearing QuickBooks Desktop (QBDT) notes in your list item. Let me share some troubleshooting to fix the issue.

Once you have entered the necessary information in the notepad and clicked OK, a dialog box asking if you want to save the changes should appear. To keep the notes, click the  OK button in this dialog box.

See the screenshot below for your reference. 

If you've done these steps and the issue persists, you'll want to ensure your QuickBooks Desktop (QBDT) is updated to the latest release. This way, we can guarantee the program runs with the newest fixes and patches. I'll show you how.

1. Go to the Help menu, and select Update QuickBooks Desktop.
2. Select the Update Now tab. 
3. Click Get Updates to start the download.
4. When the download finishes, restart QuickBooks.
5. Then accept the option to install the new release when prompted.

Refer to this link for more details: Update QuickBooks Desktop to the latest release.

If this issue persists, I suggest downloading our QuickBooks Tool Hub and running the Quick Fix My File to fix this issue. You can refer to the steps outlined in this article: Fix common problems and errors with the QuickBooks Desktop Tool Hub.

If you want to learn how to track your inventory at different locations, refer to the steps outlined in this article: Set up Advanced Inventory.

You can always get back to me if you have any other concerns about inventories in QBDT. I'll be around to help you anytime!