The JOIN table part of the output SQL does not contain ON clauses.

Hello,
I found the output sql does not contain ON clauses.
For example,
"question": "Show the stadium name and the number of concerts in each stadium."
"predicted": "SELECT stadium.Name, Count(*) FROM stadium JOIN concert GROUP BY stadium.Stadium_ID"
"gold": "SELECT T2.name , count(*) FROM concert AS T1 JOIN stadium AS T2 ON T1.stadium_id = T2.stadium_id GROUP BY T1.stadium_id"
I want to know how to get the on clauses "ON T1.stadium_id = T2.stadium_id".
Thank you.