Oracle Database Free

I'm using Oracle Free 23.7.0.25.01 from here: https://hub.docker.com/r/gvenzl/oracle-free

This is the most minimal reproducer that I could make for this bug:

create table t (t int);
insert into t values (1),(2);

create table u (u int, t int);
insert into u values (1, 1), (2, 1), (3, 2), (4, 2);

create table v (v int);
insert into v values (1),(2),(3);

create table vu (v int, u int);
insert into vu values (1, 1),(2, 1),(3, 1),(2, 2),(2, 3);

select
 t.t,
 (
   select listagg(x, ', ') within group (order by x)
   from (
     select v.v x
     from v
     where v.v in (
       select vu.v
       from vu
         join u
           on vu.u = u.u
       where u.t = t.t
     )
     group by v.v
   ) t
 ) as l
from t;

The result is this:

|T  |L      |
|---|-------|
|1  |1, 2, 3|
|2  |1, 2, 3|

When it should be this:

|T  |L      |
|---|-------|
|1  |1, 2, 3|
|2  |2      |

The correct result can be produced for example when removing the (unnecessary, in this case) GROUP BY clause:

select
 t.t,
 (
   select listagg(x, ', ') within group (order by x)
   from (
     select v.v x
     from v
     where v.v in (
       select vu.v
       from vu
         join u
           on vu.u = u.u
       where u.t = t.t
     )
     -- group by v.v
   ) t
 ) as l
from t;

Alternatively, using DISTINCT also exposes the bug:

select
  t.t,
  (
    select listagg(x, ', ') within group (order by x)
    from (
      select distinct v.v x
      from v
      where v.v in (
        select vu.v
        from vu
          join u
            on vu.u = u.u
        where u.t = t.t
      )
    ) t
  ) as l
from t;