Hello Octavie,
Thanks for the response. Unfortunately i haven't taken any traces at that point of time, when this issue occurred. But i am keeping my eyes open for the next instance. Once i see the issue reoccurring, i will take up a trace and will create a case with your support group.
As far as the issue is concerned, the client requested to remove the recipient id's and run the jobs. It worked well. The reason was that the job set up was done many years ago and would go fine with the "Spool List functionality" as on todays date.