La variable de la tabla se llena solo con un valor

Utilice BULK COLLECT y FORALL para inserciones a granel y un mejor rendimiento. El FORALL permitirá ejecutar el DML para cada fila de la colección sin requerir un cambio de contexto cada vez, mejorando así el rendimiento general.

CREATE OR REPLACE PROCEDURE get_attributes (
    p_auth_use_id  IN   NUMBER,
    p_category_id  IN   NUMBER,
    p_version_id   IN   NUMBER,
    p_result       OUT  types.cursor_type
) IS
    v_numbers sys.odcinumberlist := NULL;
BEGIN 
    SELECT s.id
    BULK COLLECT --> Bulk collect all values
    INTO v_numbers
    FROM inv_srv s
        start with s.parent_srv_id in (
          SELECT ID FROM INV_SRV 
          WHERE SRV_CATEGORY_ID IN 
            (
                SELECT id
                FROM   inv_srv_category
                START WITH parent_category_id = P_CATEGORY_ID
                CONNECT BY PRIOR id = parent_category_id
            ) 
            OR SRV_CATEGORY_ID = P_CATEGORY_ID)
        connect by prior s.id = s.parent_srv_id;

        FORALL i IN 1..v_numbers.COUNT   
        INSERT INTO your_table VALUES v_numbers ( i ); --> Bulk insert

END;