The Agent runs as root user. When this is the case, the JOB with USER specified processed by the Agent, ULIMIT for the USER is not used.
Since release R6, ESP WA Agent uses setuid to switch to the specified user ID on USER statement. Option setuid won't set ULIMIT of the user. Therefore when agent runs as root, the ULIMIT of root will be used for all JOBs regardless if they have USER specified or not.