Timesheets for future periods were submitted though the timesheet was never opened or populated.
In Classic UI you see all open time periods listed, however timesheets are normally not created until you click on the clock icon to open the timesheet.
However, if you click on the timesheet from the list page and submit that timesheet, a blank timesheet is created and submitted for approval.
Release : 15.7.1
Component : CA PPM SAAS TIME MANAGEMENT
This is working as designed.