Issues with Qty to deliver option in Customers

Hi guys. I see some inconsistency in Qty to deliver option in Customer tab. Could you please guide me to track actual delivered quantity while an invoice against isn’t created any other way? I clearly remember that the option earlier showed minus figure if goods delivered had no sales invoice or overdelivered. Please see attachment for more clarity.

Delivery note created already against customer Limited 1740 code:

Qty to deliver in Customers tab:

I also tried creating a demo invoice to see if everything working fine:

After invoice Qty to deliver in Customers tab still shows billed quantity despite full quantity delivered:

You have not given enough information to understand your situation.

I need to track deliveries to a customer which currently isn’t traceable

I was not asking about your goal. I was asking for details about the transactions you are illustrating. It is not possible to understand what happened. You also did not explain what you think is inconsistent or why.