|| concat no more working in oracle mode

SET sql_mode=ORACLE;
SET default_storage_engine=ColumnStore;
CREATE TABLE t1 (c1 VARCHAR(10),ord INTEGER);
INSERT INTO t1 VALUES ('abc',1);
INSERT INTO t1 VALUES (SPACE(0),2);
INSERT INTO t1 VALUES ('',3);
INSERT INTO t1 VALUES (' ',4);
INSERT INTO t1 VALUES (' ',5);
INSERT INTO t1 VALUES (' a ',6);
INSERT INTO t1 VALUES ('aa',7);
INSERT INTO t1 VALUES ('aabb',8);
INSERT INTO t1 VALUES ('bbaa',9);
INSERT INTO t1 VALUES ('aabbaa',10);
SELECT ord,'['||c1||']','.'||COALESCE(TRIM(LEADING 'a' FROM c1),'NULL')||'.' FROM t1 ORDER BY ord;

now gives:
ERROR 1178 (42000): The storage engine for the table doesn't support MCS-1001: Function 'concat' isn't supported.

before it was giving same result as for InnoDB with mtr test oracle.func_trim_oracle