Let's go over the email triggers and how they work and how certain settings will override those triggers.
Program Scheduling Notification Message
If the Program Scheduled release 'Notification message' is set within a program, which you can find by going to Programs > choose Program > Publish > "Scheduled" that will override the 'New Content Available' template in Settings > Emails.
If the Program schedule release 'Notification message' is left empty then the 'New Content Available' template will be used provided it is enabled which is set in Customization > Email templates.
If multiple Programs are scheduled to be released at the same time they will each fire off their own trigger. This means if the 'Notification message' is set for each of them there will be 3 emails sent. If no 'Notification message' is set then 3 emails will still be sent but will each use the 'New Content Available' template.
Any Program that has a scheduled release date will always trigger an email to be sent unless:
A) There is no 'Notification message' set within the Program Publish tab.
B) The 'New Content Available' template is disabled.