Inconsistent results for make_set of cast

-- case 1

CREATE TABLE t1 (c1 SMALLINT);

INSERT INTO t1 VALUES (9067);

SELECT CAST((MAKE_SET(c1, (CAST(c1 AS BINARY)), (TRIM((CAST((CAST(((CAST(0 AS DOUBLE)) > (CAST(0 AS NCHAR))) AS NCHAR)) AS SIGNED)))), NULL)) AS CHAR) FROM t1; -- { ???,0}

-- case 2

CREATE TABLE t1 (c1 INT);

INSERT INTO t1 VALUES (9067);

SELECT CAST((MAKE_SET(c1, (CAST(c1 AS BINARY)), (TRIM((CAST((CAST(((CAST(0 AS DOUBLE)) > (CAST(0 AS NCHAR))) AS NCHAR)) AS SIGNED)))), NULL)) AS CHAR) FROM t1; -- {0???,0}