10008: Label class <value> has a label expression that uses unqualified field names for fields that exist in more than one table
Your layer has a label class with an 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.
Solutions
Do one of the following:
Review the draw metrics for this layer. If you are sharing the layer, review the data access metrics for the service. Learn more about performance in ArcGIS Pro.
If changes are needed, provide a more qualified field name to identify the specific table to use.
Additional information
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.