By default, the system run the data in the early morning if employees have clocked in/out. Therefore, sometimes when the employee has only clock in or out, or just finished clocking in/out, the system will not count the hours worked. You need to click the Calculate in [Attendance] > [Overview] to run the working hours.
If there is still no change after pressing the operation, please check:
Whether the employee clocks in and out in "field work"?
Whether the employee has assigned shifts?