Symbol has outputs with duplicate names.
The symbol definition has duplicate output names.
The symbol definition has outputs that have same name.
This is a bug in the Symbol Definition. This can lead to several issues:
Only one of the outputs can be bound when required.
Copying and pasting these symbol occurrences results in multiplying of outputs.
What You Should Do
Run the Diagnostic Clean Database Issues Report.
Find the corresponding record in Diagnostic Clean Database reports, and find the name of the Symbol Definition of the entry in Comments column.
An administrator is responsible for analyzing the symbol definition and fixing the duplicate output names.