If you're referring to the PID - thats the process ID that the operating system provides to the UBE Process. PID numbers get reused on various platforms, so its likely that the PID will be the same for a few jobs over a long period of time. Its not uncommon, and there should be no cause for concern.
I'd be very concerned if the same JOB number was assigned to two different UBE processes on the same box though.