As a part of 15.8 upgrade the notifications are enabled in production but we requested only for PM/RM to send manual reminders on reportees timesheets but resources (who are not PM/RM) are getting notified about timesheet submission status of random resources..
Release : 15.8
Component : CA PPM SAAS TIME MANAGEMENT
The reason some resources were getting timesheet submission notification was because of the OBS unit they belonged to had "Resource - Approve Time" right for over 200 resources.