Map service does not honor duplicate field names

Description

After joining a table to a feature layer in ArcMap and publishing the map to ArcGIS Server, some fields appear to be missing when a feature is Identified. This behavior occurs when the map service is consumed in any client.

Cause

If duplicate field names exist between the two joined tables, one of the duplicate fields will not appear.

Solution or Workaround

1. In ArcMap, open the source map document.
2. Right-click the layer that is joined to a table and select Properties. Select the Fields tab.
3. For the field name that is duplicated, change the Field Alias name.
4. Click OK to apply the changes and close the Layer Properties dialog box.
5. Save the map document. When using an ESRI Optimized Map Service, overwrite the existing MSD file using the Save Map Service Definition file.
6. Restart the map service.