Backpatching this to 12 shows yet another problem -- the topmost
relation acquires additional FK constraints, not yet sure why. I think
we must have fixed something in 13 that wasn't backpatched, but I can't
remember what it is and whether it was intentionally not backpatched.
Looking ...
--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
"I can see support will not be a problem. 10 out of 10." (Simon Wittber)
(http://archives.postgresql.org/pgsql-general/2004-12/msg00159.php)