I generated my first invoice for a client. It should be a recurring one on a yearly basis. I created the invoice and sent it out, then proceeded to follow the instructions found at https://github.com/InvoicePlane/InvoicePlane/wiki/Recurring-Invoices, but I am not able to set it as recurring. It seems that it only applies to new invoices in draft state, not when the invoice is set to read only due to it being sent via email already to the customer.
It seems strange that I cannot still create a recurring invoice based off this one just because an email was sent to the customer. Is this by design? Is this a bug?