Hi Bhagee,
Routing operation is not deleted, operation allocation to components got deleted.
Its because some modification happened @ BOM level.
I think same component 1009333GEE deleted and again added in BOM. That is the reason for allocation lost in routing.
Please check while changing the BOM what activities are performed? Is it any Z development done in system for bridging the BOM
Regards,
Amarnath Dube