When you record an invoice for billable time, QuickBooks changes the billing status from not billed to billed. The status doesn't change back to not billed even if you edit or delete the invoice. You have to manually change the status if you want to make time billable again.
To do this task
Open the timesheet for the time data you want to change.
On the timesheet, click the billed icon:
Answer Yes to the question that appears.
Save the transaction.
Troubleshoot invoice problems