When using the SSH process option 
(to a linux or a mac machine)  we experience an unhandled exception:

id=56]#011INFO#011hudson.plugins.ec2.EC2Cloud#log: Launching remoting agent (via SSH client process): ssh -o StrictHostKeyChecking=no -i /tmp/ec2_3397513313008332222.pem ubuntu@192.168.12.224 -p 22 /usr/bin/java -jar /tmp/remoting.jar -workDir /home/ubuntu
Jul 10 19:14:02 ip-192-168-12-216 systemd[1]: jenkins.service: Main process exited, code=killed, status=9/KILL
Jul 10 19:14:02 ip-192-168-12-216 systemd[1]: jenkins.service: Failed with result 'signal'.

This results in rebooting the system, and will loop when you have ec2 machines configured to be available.

When we turn off this option and use the 'Trilead SSH2 Connection' the issue does not happen.

This might be related to an update on the SSH client on the jenkins server (something that occurred on our server 6 days prior)

This is what I found in the apt logs a few days earlier::

Start-Date: 2024-07-02  06:10:39
Upgrade: openssh-client:amd64 (1:8.9p1-3ubuntu0.7, 1:8.9p1-3ubuntu0.10), openssh-server:amd64 (1:8.9p1-3ubuntu0.7, 1:8.9p1-3ubuntu0.10), openssh-sftp-server:amd64 (1:8.9p1-3ubuntu0.7, 1:8.9p1-3ubuntu0.10)
End-Date: 2024-07-02  06:10:41

Oddly enough that was 8 days earlier.

The issue on the jenkins server started on 2024-07-10

I wonder if I am the only one who is dealing with this issue, or if others experienced also issues recently