We discussed one of the traditional ways to configure HAProxy with PostgreSQL in our previous blog about HAProxy using Xinetd. There we briefly mentioned the limitation of the HAProxys built-in improvements to HAProxy like this commit which improves the disconnection of pgsql-check. So messages like [crayon-5dc9d43083589337470863-i/] may not appear in the logs. This is tested [&]

https://www.percona.com/blog/2019/11/08/configure-haproxy-with-postgresql-using-built-in-pgsql-check/