> psqlrc is not shared among users and each user will use psqlrc from the pgAdmin user storage directory.
I think so, too.
When only UserA begins, UserA's psqlrc work. UserA's $PSQLRC: db=> \! echo $PSQLRC /var/lib/pgadmin/storage/usera/.psqlrc
But this case, other user's psqlrc had run. 1) UserA clicks PSQL Tool. 2) UserB clicks PSQL Tool before UserA's PSQL begins. 3) UserA's PSQL run UserB's psqlrc.