Activated Purchasing in ECC So Workflow is disturbed

Hi Experts,

                 Recently we have activated purchasing data source And successfully created delta environment in ECC and delta is flowing properly but all of at sudden workflow is disturbed in ECC And it is triggering multiple mails to the user (Around 5000 mails).

Is it for same reason or for different reason.

Please tell me if we create Delta Environment for the first time what are the precautions we have to take.

Thanks in Advance.

Praveen