I have created a form plugin which will leverage with Microsoft Graph Api to get data from SharePont list and display it as a dropdown component.
I have set the required property in the getMetaConfig().

I also have the on change event to capture values from the selected option and return the Title and id as object.

When I import the form plugin in NAC, the label able to display the title and id from the object that return from the component.

However, the component will always recognize there is no value return, and the required field validation will shows even I have selected an option.
I have also tried to change the return data type from object to string and keep the same for the rest. And it will work. When the drop down is selected, the selected value (string) could be display in a label control and the component manage to recognize there is already a selected value.
I am wonder if there is any additional steps is required if the return data type need to be in object data type.