The fields are there in the popup but they show zero values. And I did confirm that the fields were checked as visible when the map service was published. And as I posted originally, if I add the feature layer to the ArcGIS Pro map at the map service level, as opposed to the layer level, it does show the AREA field values, not zeros, from Identify (popup).
We'd like our ArcPro users to be able to take advantage of using our published map feature layers in their ArcPro projects, but if the Area and Length fields do not show the values then we can't provide this option.
Background:
ArcGIS Server 10.7.1 - Windows
ArcGIS Pro 2.5.2