BigQuery error: Name f0_ not found inside t0 at [3:11]

I'm getting the error 'BigQuery error: Name f0_ not found inside t0 at [3:11]' when trying to load this query on DataStudio. It runs fine on big query so I'm guessing data studio doesn't like it. I'm very new at data studio.

SELECT avg(Num_Apps)
    FROM
        (SELECT
        user_pseudo_id,
        COUNT(DISTINCT(app_id)) AS Num_Apps 
        FROM
        `TABLE_current_app`
        GROUP BY 1)
    as counts