Even though "Send report data with emails" is enabled in the Enforce server general settings users are unable to see the CSV option when scheduling distribution of a report.
The below option is missing:
DLP 15.8 or later.
On top the the Enforce general settings the role assigned to the users needs to have the "Email incident report as CSV attachment" permission assigned. Otherwise the option will remain hidden for them.
To enable the users to schedule report distribution and to allow them to use the CSV option it will be necessary to review the role configuration which is assigned to them. The "Email incident report as CSV attachment" permission is listed in the Incidents section of the General tab. To grant this right to the role the checkbox must be marked.
After granting the permission save the changes. The user/s will need to relog to apply the new permissions to their profile.
For more details on role configuration, including description of the permissions, refer to the below technical document: