select * into file from (select ... group by) produces spurious error

drop table if exists `C2`;
CREATE TABLE `C2` (
`intc` int(6) DEFAULT NULL,
`id` int(11) NOT NULL,
`mm_prezzo` decimal(12,0) DEFAULT NULL
) ENGINE=Columnstore DEFAULT CHARSET=utf8;

select * into outfile '/tmp/result.dml' from (SELECT id,intc FROM C2 WHERE intc IN (201909) GROUP BY id,intc) as sel1;
ERROR 1815 (HY000): Internal error: IDB-2021: 'intc' is not in GROUP BY clause. All non-aggregate columns in the SELECT and ORDER BY clause must be included in the GROUP BY clause.