How to get SYS_AUTO_SQL_TUNING_TASK to respect PUBLIC synonyms ?

12.2 Autonomous Health System - SQL Tuning

First, acknowledgement that public synonyms are evil and should be avoided.     We bought the app and unfortunately they came in the basket.

I've tried several usernames other than the value 'UNUSED' below, and in all cases analysis fails on candidate SQL that relies on public synonyms (some USERNAMEs fared better than others obviously ...)..

How to get SYS_AUTO_SQL_TUNING_TASK to respect PUBLIC synonyms ?    Awaiting my d-oh moment ... via your response ... alex

Here are my last settings:

SELECT parameter_name, parameter_value

FROM   dba_advisor_parameters

WHERE  task_name = 'SYS_AUTO_SQL_TUNING_TASK' order by 1,2;