Query used for checking foreign key triggers
returns too many results when there're more than one foreign
key in a table. It happens because only table's oid is used to
link between pg_trigger with INSERT check and pg_trigger with
UPDATE/DELETE check.

I think there should be enough to add following conditions
into WHERE clause of that query:
        AND     pt.tgconstrname = pg_trigger.tgconstrname
        AND     pt.tgconstrname = pg_trigger_1.tgconstrname

/Constantin