Wrong result upon query with join and distinct

CREATE TABLE t1 (a INT);

INSERT INTO t1 VALUES (1),(2);

CREATE TABLE t2 (b VARCHAR(1024)) ENGINE=MyISAM;

INSERT INTO t2 VALUES ('-a'),('-W'),('-f'),('-FANTW'),('-c'),('b'),('r');

CREATE TABLE t3 (c VARCHAR(1024), d VARCHAR(1024)) ENGINE=MyISAM;

INSERT INTO t3 VALUES

  ('-D-','-r-'),('-i-','-j-'),('-e-','h'),('y','-I-'),('-Y-','-G-'),

  ('-QMCQI-','-J-'),('p','-V-'),('z','s'),('-b-','a'),('-l-','-c-'),

  ('-NACAU-','-FBFMW-'),('-S-','c'),('c','-b-'),('-R-','-e-'),('x','-t-'),

  ('-N-','b'),('-c-','-u-'),('-Q-','c'),('-a-','-m-'),('e','-R-'),('-s-','-y-'),

  ('c','-d-'),('-p-','-y-'),('-r-','-x-'),('-O-','-e-'),('-i-','-c-'),

  ('n','-p-'),('p','-c-'),('e','c'),('-c-','-v-'),('-J-','-H-'),('-P-','p'),

  ('-T-','-x-'),('-v-','-w-'),('-D-','f'),('-p-','-O-'),('-p-','-E-'),

  ('-i-','-K-'),('-a-','-H-'),('f','x'),('-O-','-g-'),('-p-','-c-'),

  ('-c-','-C-'),('-A-','l'),('f','-B-'),('-x-','-G-'),('r','-I-');

SELECT DISTINCT b, c FROM t1 JOIN t2 JOIN t3 WHERE b < d ORDER BY b, c;

DROP TABLE t1, t2, t3;

...

-f      p

-f      r

-f      r

-f      x

...

commit 636f154bb49b301d5c5272870ac7eba439864b90

Author: Arcadiy Ivanov

Date:   Tue Jul 28 16:01:37 2026 -0400

    MDEV-40376 `Protocol::end_statement` assertion when window function fills HEAP tmp table