Thanks for coming back, @ian-figtreehomes. I'm here to share additional insights about progress invoicing. 

It could be that the invoice isn't in the full amount, that's why it still showing as unbilled on your second invoice. Please know that the estimate status automatically changes to Closed once you’ve invoiced for the full estimate. 

Should you try to invoice for more than 100% of the total estimate, you’ll only be able to add what’s left of the remaining balance.

To resolve this, please ensure the invoice is in a full amount for a specific item so it will not show up on your second invoice as unbilled. 

Check out Create progress invoice from the estimate in this help article: Set up and send progress invoices in QuickBooks Online.

You might want to include estimate summaries on your progress invoices in QuickBooks Online. Read through this article for future reference: Add project estimate summaries to a progress invoice. 

Feel free to message again if you have additional questions. We're always here to guide.