Hello
Thank you for report!
I reproduced this bug in REL_11_2, but not in REL_11_STABLE. Seems already fixed in stable branch by commit https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=925f46ffb82f0b25c94e7997caff732eaf14367d and therefore will be shipped in next minor update 11.3 (scheduled for May 9).
regards, Sergei