When using GROUP BY with JSON_ARRAYAGG with joint table, the square brackets are not included

create table owner(

    id int primary key,

    name varchar(50)

);

create table test_table(

    id int primary key,

    type varchar(50),

    size int,

    color varchar(50),

    owner_id int,

    FOREIGN KEY(owner_id) REFERENCES owner(id)

);

SELECT name, owner.id, JSON_ARRAYAGG(JSON_OBJECT('id',tt.id,'type',tt.type,'color',tt.color)) as materials from owner LEFT JOIN test_table tt on owner.id = tt.owner_id GROUP BY owner.id;