There are 3 issues of changing the period of Attendance(Progress Check).

Learning in time → changing the start date and time later than the learning date and time

FAQ: Learning before recording

EX.

https://support.coursemos.kr/attachment/view/3689/clipboard.png

A student is present if he/she completes learning within the attendance(progress check) period.

In this case, even if you change the start date and time of attendance period later than the student's learning date and time,

the student's existing learning record will be changed to 'Learning before recording' and 'Present  → Absent'.

If the student has completed learning before the period is changed, the VOD play bar has already moved to the end, so the learning time will not be recorded even if the student learn again within the changed period.

(Caution)

Pre-period Learning → changing the start date and time earlier than the learning date and time