There is a known issue related to assigning a work schedule in HCM Time & Labor.
If you attempt to assign a work schedule for an employee by navigating through Time & Labor (Main Menu > Time and Labor > Enroll Time Reporters > Assign Work Schedule), you might receive an error.
To assign a work schedule, navigate to Main Menu > Manager Self Service > Time Management > Manage Schedules > Assign Work Schedule. There is no change to the functionality or use of assigning a work schedule through this navigation. You will notice the screen looks exactly the same as it would if you were navigating through Time & Labor.
For directions, please refer to the topics titled Assign a Work Schedule (for Salaried and Exception Hourly Employees Only) and Change Work Schedules on pp.37-39 of HR3 New Hires and Job Data Guide v2.0.pdf.