Configure stock item for name and code

I’m building a system based on V14.1.0

I want to have item_name based on descriptive text and item_code based on my company naming system.

When I create a new item the popup form displays entry boxes for both item_code and item_name as expected.

But when the full form is opened, the field for item_code is shown but item_name is completely missing from the full form even though it is not hidden in the form customisation.

How do I get item_name to display?

A further conundrum is when I attempt to rename the form the dialog presents two fields (both displaying item_code data) and perplexing labels “New Item Name” and “New Name” data. I expected this should be “New Item Name” and “New Item Code”

I suspect a code corruption (rather than a configuration) issue.

What am I missing and how might I make a repair?