BUG #18001: Invalid subquery passed as true

The following bug has been logged on the website:

Bug reference: 18001
Logged by: Piet van Ham
Email address: pvham90(at)gmail(dot)com
PostgreSQL version: 11.20
Operating system: Linux
Description:

create table table_a (column_a varchar(16), column_b varchar(16));
create table table_b (column_c varchar(16), column_d varchar(16));

insert into table_a (column_a, column_b) values ('row1a','row1b');
insert into table_b (column_c, column_d) values ('row2a','row2b');

delete from table_a where column_a in (select column_a from table_b); --the
subquery is invalid, but the where clause is passed as true resulting in all
records deleted

select count(*) from table_a;
-- 0