Successfully Send Event Invite to Employees and not to Employees Set as Contacts

User selects an attendee for an Event, Employee names may appear twice in the list:

1. Navigate to Activities > Scheduling > Events > New.
2. Attendees tab > add Employees to be invited.
3. Select the name of an employee from the dropdown list.
4. The list shows multiple names of the same Employee because the list includes both the employee record and contact record for that user. 
5. This is true when Show Employees as Contacts is marked in Setup > Company > General Preferences.

To successfully send the invite, select the Employee record instead of the Contact. Filter the list of attendees that is selected for the event.
1. Navigate to Activities > Scheduling > Events > New.
2. In the Attendees tab, add Employees to be invited.
3. Before selecting the name of an employee from the dropdown list, filter the list.
4. On the line item, click on the >> icon then click on List.
5. On the Choose Send Invitation To pop-up window, set the filter to Employee.
6. This automatically trims down the list to show Employee records only.
7. Select the Employee.
8. Repeat steps when entering additional employees.
10. Enter Title.
11. Click Save.