\d t: ERROR: XX000: cache lookup failed for relation

Is that considered an actionable problem?

Encountered while trying to reproduce the vacuum full pg_statistic/toast_2619
bug; while running a loop around VAC FULL and more in another session:
[1]- Running { time sh -ec 'while :; do psql --port 5678 postgres -qc "VACUUM FULL pg_toast.pg_toast_2619"; psql --port 5678 postgres -qc "VACUUM FULL pg_statistic"; done'; date; } &
[2]+ Running time while :; do
psql postgres --port 5678 -c "INSERT INTO t SELECT i FROM generate_series(1,999999) i"; sleep 1; for a in `seq 999`;
do
psql postgres --port 5678 -c "ALTER TABLE t ALTER i TYPE int USING i::int"; sleep 1; psql postgres --port 5678 -c "ALTER TABLE t ALTER i TYPE bigint"; sleep 1;
done; psql postgres --port 5678 -c "TRUNCATE t"; sleep 1;
done &

[pryzbyj(at)kgfs66telsadb ~]$ psql --port 5678 postgres -x
psql (11beta1)
Type "help" for help.
...
postgres=# \set VERBOSITY verbose
postgres=# \d t
ERROR: XX000: cache lookup failed for relation 8096742
LOCATION: flatten_reloptions, ruleutils.c:11065

Justin