Hello Ramesh
Did you check the table HRUS_D2???
There are validity dates.... so the system does a select keeping the current date in Mind. The record are there in the system, only they are not picked up if they have expired. There is no job, a simple select is there. Go Ahead and debug the FM RH_SUBSTITUTES_LIST and you will find a select with date range!
Regards,
Modak