Send an email task failure of event studio

[devardekartb]

We are using the event studio to send the reports to users.The reports involves bursting and the reports will be sent to different mail ID's according to output bursted for them only.When We used the email ID column in "To Section" of event the bursting worked perfectly but when the same Email ID column is placed in "Bcc Section" all the outputs are sent to all the users. This is impacting us so please respond if you have any idea of this behaviour of cognos event studio.