pgBouncer - got packet 'D' from server when not linked WARNING messages

[fatih abztn <fatihabztn@xxxxxxxxx>]

Hi everyone;

     We use pgBouncer for pooling, we see like these messages in pgb logs;

WARNING S-0x118b7c0: db/username@dbip:port got packet '2' from server when not linked
WARNING S-0x118b7c0: db/username@dbip:port got packet 'T' from server when not linked
WARNING S-0x118b7c0: db/username@dbip:port got packet 'D' from server when not linked
WARNING S-0x118b7c0: db/username@dbip:port got packet 'C' from server when not linked
WARNING S-0x118b7c0: db/username@dbip:port got packet 'Z' from server when not linked
WARNING S-0x1170a88: db/username@dbip:port got packet '1' from server when not linked
WARNING S-0x1170a88: db/username@dbip:port got packet '2' from server when not linked
WARNING S-0x1170a88: db/username@dbip:port got packet 'T' from server when not linked
WARNING S-0x1170a88: db/username@dbip:port got packet 'D' from server when not linked
WARNING S-0x1170a88: db/username@dbip:port got packet 'C' from server when not linked
WARNING S-0x1170a88: db/username@dbip:port got packet 'Z' from server when not linked

Actually there are different types messages also but we think all of them independent. one of them is above.

others like these:

- bla bla pooler error: server conn crashed?

- FIXME: query end, but query_start == 0

  FIXME: transaction end, but xact_start == 0

and our environment:

PgBouncer 1.17.0
libevent 2.0.21-stable
adns: evdns2
tls: OpenSSL 1.0.2k-fips  26 Jan 2017

mode is transaction

avr TPS = 20K 

postgres version 14.5

Have you encountered this problem before, what causes this and what is the solution?

Thanks in advance...