Your layer has a label class with a label expression that uses unqualified field names for fields that exist in more than one table. Ambiguous field names in more than one table of a join will give unknown results when used for draw and query operations.
Check the drawing performance for your layer or basemap layer in ArcMap. If you are publishing, check the drawing performance for your service in the Preview window.
- If you see the need to make changes, provide a more qualified field name to identify the specific table to use.
You can append the table name to the field name to provide a qualified name for the field you want to use.
Specify field names in label expressions as TableName.FieldName.
This naming convention helps prevent duplicate field names when the target dataset and a join table have common field names.