PDM is designed to NOT send notifications to the user who runs the transition where a notification is sent even if the user running the transition is in the group getting the notification. PDM assumes the user running the transition already knows about the transition (release) so it won't send them the notification.
Consider using an automated task add-in to run the release transition like "Transition Time" (found here). Then you can automatically release all drawings in the pending release state at 3pm everyday using the Admin account and everyone gets the notifications. This email will be like a daily release broadcast because ALL drawings that get released that day were collected in one email.
This will enhance your workflow significantly and stop the flood of email notifications.
Hope this helps.