When you start ArcGIS Pro without a map, there is no apparent way to view the intermediate table of a relationship class. In ArcMap you could click in the Relationship an view the attributed table. In ArcGIS Pro you have to add both participating tables to the ToC of the map to see the intermediate table. In the ArcGIS Pro catalog, "This item doesn´t support table view."
Please add support to view the table view attributed relationships in the ArcGIS catalog within ArcGIS Pro
Populate an attributed relationship class table (intermediate table)—ArcGIS Pro | Documentation
