pgpool-II: cannot use serializable mode in a hot standby

Hi.

We have application which explicitly does
set default_transaction_isolation to 'serializable' .
It is connected to PostgreSQL master/slave cluster through pgpool-II
(pgpool2 3.4.3-1.pgdg70+1). Our logs are filling with

ERROR: 0A000: cannot use serializable mode in a hot standby DETAIL:
"default_transaction_isolation" is set to "serializable". HINT: You can
use "SET default_transaction_isolation = 'repeatable read'" to change
the default. db netstat, client 10.160.1.38, user nf2pg LOCATION:
GetSerializableTransactionSnapshot, predicate.c:1588 STATEMENT: DISCARD ALL

It seems pgpool sends these statements to the slave server. Is it
pgpool/application misconfiguration or pgpool issue?

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Best regards,
Alexander Pyhalov,
system administrator of Southern Federal University IT department