Internship/Thesis Settings / Internship/Thesis Settings / Internship and Thesis / Internship Settings / Allow Attendance Approval by employees only x days after initial submission
Here, you define the maximum number of days after the due date that an employee can approve attendance for Internship/Thesis. (Please note that if set to 0 then there is no limit)
Example
Setting -> 5 (Employee can approve attendance for up to 5 days before the present date)
Setting -> 2 (Employee is not able to submit attendance for that date any more since more than 2 days have passed)