A logic bug of subquery with reference table in citus 13.0.1

[duerwuyi]

How to reproduce

Citus version： Citus 13.0.1 on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit
Postgres version: PostgreSQL 17.2 (Debian 17.2-1.pgdg120+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit
init state:

DROP TABLE IF EXISTS t2;
create table t2 ( 
vkey int4 ,
pkey int4 ,
c10 numeric ,
c11 text ,
c12 int4 ,
c13 int4 ,
c14 text ,
c15 timestamp ,
c16 numeric ,
c17 numeric 
);
DROP TABLE IF EXISTS t4;
create table t4 ( 
vkey int4 ,
pkey int4 ,
c22 numeric ,
c23 text ,
c24 timestamp 
);
DROP TABLE IF EXISTS t6;
create table t6 ( 
vkey int4 ,
pkey int4 ,
c26 text ,
c27 timestamp ,
c28 int4 ,
c29 int4 ,
c30 int4 ,
c31 numeric ,
c32 numeric ,
c33 numeric 
);

SELECT create_reference_table('t2');  
insert into t6 (vkey, pkey, c26, c27, c28, c29, c30, c31, c32, c33) values 
(2, 12000, '', make_timestamp(2037, 2, 3, 13, 55, 31), 69, 0, -0, 82.49, -92.9, 40.7);
insert into t4 (vkey, pkey, c22, c23, c24) values 
(5, 15000, 0.0, ']]?', make_timestamp(2071, 10, 26, 16, 20, 5));
insert into t2 (vkey, pkey, c10, c11, c12, c13, c14, c15, c16, c17) values 
(14, 24000, 28.66, '9rVx', -98, 79, '`', null::timestamp, 56.17, 98.30);
insert into t2 (vkey, pkey, c10, c11, c12, c13, c14, c15, c16, c17) values 
(28, 38000, -0.0, 'f+', -85, null::int4, '', make_timestamp(2033, 3, 8, 1, 20, 19), -65.55, -22.74);

query

update t6 set 
  vkey = 43
where exists (
  select distinct 
      t6.c29,
      (select c15 from t2)
    from
      t4
)

result: 0 rows updated

Excepted result:

the subquery should have rows to match the "EXISTS" clause, so the correct result should be: 1 row updated.

if I changed the query into:

update t6 set 
  vkey = 43
where exists (
  select distinct 
      t6.c29
    from
      t4
)

the answer will be correct.