Calculated Field displays but is not visible

Pega Academy Business Architect Mission

Requirement is to display the full name as a concatenation of first and last name

The data object correctly concatenates the fields but when it is included in a UI it displays but is not visible.

I know it is displaying because when I use the field in a dropdown I get multiple blank entries and selecting different blank entries populate the other fields correctly.

@AndrzejR - Verify the case harness rule in advanced tab whether “Enable expression calculation” checkbox is enabled or not? It should be enabled to run the calculations.

Thank you.