Consider the following statements:
CREATE TABLE t0(c0 PRIMARY KEY, c1);
INSERT INTO t0(c0) VALUES (x'bb'), (0);
SELECT COUNT(*) FROM t0 WHERE INSTR(x'aabb', t0.c0) ORDER BY t0.c0, t0.c1; -- 1
SELECT * FROM t0 WHERE INSTR(x'aabb', t0.c0) ORDER BY t0.c0, t0.c1; -- no row is fetched
The two SELECT statements disagree, since the WHERE clause in the first query seems to evaluate to TRUE for one row, and for the second query the WHERE clause seems to evaluate to false for both rows.