Hi Sreenu,
please check SOURCE_REL_IND = X on position level of your SC (Table BBP_PDIGP). It Should be so.
Also Check field ISOURCE_REL_IND in the table BBPD_PD_INDEX_I for corresponding entries.
If you serach with SC number - search should run via BBP_PDIGP Table.
If you search via item data (for example purchasing group) - search can run via table BBPD_PD_INDEX_I
Regards
Konstantin