After the recent update launching SSH agent fails on Ubuntu 16.04.

The same Jenkins successfully launches SSH agents on Ubuntu 18.04. Here is the launching log:

SSHLauncher{host='XXX', port=22, credentialsId='jenkins-ssh', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=60, maxNumRetries=10, retryWaitTime=15, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.KnownHostsFileKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true}

[08/07/23 08:31:32] [SSH] Opening SSH connection to XXX:22.

Searching for XXX in /var/lib/jenkins/.ssh/known_hosts

Searching for XXX:22 in /var/lib/jenkins/.ssh/known_hosts

[08/07/23 08:31:33] [SSH] SSH host key matches key in Known Hosts file. Connection will be allowed.

[08/07/23 08:31:33] [SSH] Authentication successful.

I tried to delete the agent and add it again, clean the working directory, and update remoting.jar manually but nothing helped.

/var/log/auth.log on the server with agent:

Aug  7 10:31:33 content sshd[30983]: Accepted publickey for jenkins from XXX port 60808 ssh2: RSA SHA256:IF9pR6RlJ/qejF9yz2W2LygPR9nUmHJMmYaxFx0Jmr4
Aug  7 10:31:33 content sshd[30983]: pam_unix(sshd:session): session opened for user jenkins by (uid=0)
Aug  7 10:31:33 content systemd-logind[839]: New session 9834 of user jenkins.
Aug  7 10:31:33 content systemd: pam_unix(systemd-user:session): session opened for user jenkins by (uid=0)

Process list shows ssh session from user jenkins:

root     30983  0.0  0.0  92836  6864 ?        Ss   10:31   0:00  _ sshd: jenkins [priv]
jenkins  31011  0.0  0.0  92836  3332 ?        S    10:31   0:00      _ sshd: jenkins@notty