Unable to check "Has Serial No" after saving new item

When I create item and save it without checking “Has Serial No”.
Some time I can check this option after submitting and sometimes not.

It’s disabled when there’s stock movement against the item. Until then you can change it.

ref: erpnext/item.js at 71435569b02d7ed5dae1eb8030d83065ff09a2e4 · frappe/erpnext · GitHub