joudaon Please send an email to the jenkinsci-users mailing list for a general investigation like this. In your email, add the output from once you enable LAUNCH_DIAGNOSTICS, and some details about whether this was working for you previously, and if so with what version of the plugin and Jenkins, what version of Jenkins you are running, what OS you are using on the Jenkins master and the agent being used by the shell step, how the agent is configured, what other configurations you have tried, etc.
Basic guidance on how to enable LAUNCH_DIAGNOSTICS is here. The property you want is named org.jenkinsci.plugins.durabletask.BourneShellScript.LAUNCH_DIAGNOSTICS, and you want to set it to true. Exactly where the system property is specified will depend on how you run Jenkins. From your last ticket, it looks like you are running it as a service, so you want to configure the Java arguments in the service configuration. Once you have it set correctly, the message "running Jenkins temporarily with -Dorg.jenkinsci.plugins.durabletask.BourneShellScript.LAUNCH_DIAGNOSTICS=true ..." will no longer be present in the build log, and hopefully the actual error will be printed to the build log for the failing build, which you should include in your email.
I am going to close this issue for now, if it looks like there is a bug after you provide more info on the mailing list, we’ll reopen the ticket, so please do not open another ticket for your issue.