GetLoggedInUser() returns valid user ID but null display name

Like the title says user ID returns fine but display name is null;

DUC appears to have been approved for both ID and username.

Below is the code for the callback used when the GetLoggedInUser() request completes:

private static void GetLoggedInUserCallback(Oculus.Platform.Message<User> message)
{
if (!message.IsError)
{
User user = message.GetUser();
PlayFabManager.Login(user.ID.ToString(), user.DisplayName);
}
}