Welcome back to the Community! Thanks for the update! I recommend searching for the invoice transaction using the invoice number at issue to confirm whether one exists. If you've found transactions with the exact invoice numbers, you can perform actions such as editing or deleting them. Also, I suggest temporarily turning off Custom transaction numbers in your sales settings and running a sample invoice to help us further isolate the problem.
Let me know if the issue persists! I will be around to help.
