BUG #18141: sorry, too many clients error occurring very frequently

The following bug has been logged on the website:

Bug reference:      18141
Logged by:          Ravi Agrawal
Email address:      ravi.s.agrawal23@gmail.com
PostgreSQL version: 13.11
Operating system:   RHEL
Description:

Hi Team,

We have updated PostgresSQL from version 13.4 to 13.11 and observing 'sorry,
too many clients' error very frequently.
Connection count is shooting up on performing basic operations  and crossing
the max_connections value. This has not been observed previously on Postgres
v13.4 
We need to understand if this issue is caused due to the change in version.
Is there any history of known incidents facing this issue with the specific
version of PostgreSQL.

Appreciate your response on this.

Many Thanks,
Ravi Agrawal