Issue: Sales Order Not Closing After Converting to Invoice

I am facing an issue while converting a Sales Order into an Invoice. Instead of using the original item from the Sales Order, I am removing it and adding it again from "Include Unbilled Items." However, after generating the invoice, the Sales Order status remains "Confirmed" instead of changing to "Closed."

I use Sales Orders because it is a customized work, allowing me to record when I received the order and its delivery date. I mark the bill as billable since I am subcontracting the work, enabling me to add the markup directly in the bill and seamlessly include it while invoicing.