The P4TICKET variable will randomly disappear in jobs running on the Jenkins Master. This is job specific as other jobs running on the Master will continue to use the ticket properly. This causes any jobs that rely on the existence of the P4TICKET variable to randomly fail. So far I have not found a reliable work around to force the jobs to start using P4TICKETS in it's P4 commands again. Forced logout/login with -a and restarts of Jenkins and the Master Node have not worked.