If you can’t find a specific entry when it’s time to create an Invoice, there are a few things that may have caused it.
The first, is that you may have accidentally tracked it as unbillable time. Try checking the Contact, Project, Tasks and User associated with the time entry to see if they are checked as unbillable or have an hourly rate set to 0.00/hr.
Another, is that you may have already invoiced it. Head to the Report tab and see if you can locate it there.
If you are still having trouble locating missing entries, email firstname.lastname@example.org.