If the employee Attendance Info screen is showing the employee as half/full day absent the reason could be the employee attendance is calculated based on the actual hour completed by the employee as per their shift policy. If in case the employee's actual hour is less than the work hour defined for the specific shift; then attendance will show absent.
Resolution:The employer should be aware of the attendance policy configured for each attendance scheme in their organization to manage the attendance on greytHR. You can also share your company attendance policy to your employees using greytHR forms. Navigate to HR forms page from the employee >> setup section >> and fill the details and share the same with your employees.
Click on the below link to know more about greytHR's attendance policy configuration.
http://docs.greytip.in/display/GOIN/Create+an+Attendance+Policy