When working in the Form Designer, configuring the label of a field in a child...

Configuring the label of a field in a child table changes the label only on that table, not on the base table or the parent table. The base table is the table that contains the common fields for all the extended tables, and the parent table is the table that is directly extended by the child table. The label of a field on the base table or the parent table can be different from the label on the child table. References: [ServiceNow Docs - Table extension], [ServiceNow Community - How to change field label in child table]