Issue with spliton using dapper.net inner join

I have the following sql query which is executed via dapper.net

  var resultList = sqlCon.Query<UserProfile, UserAddress, UserProfile>(@"

                            UPDATE [User].[User_Profile]
                                SET ProfileStatus = 4
                            WHERE Id = @UserId

                            SELECT u.Id [UserId], u.Username, u.Age,
                                   u.ProfileStatus,
                                   a.Id [AddressId], a.Country, a.[State], a.City,
                                   a.Latitude, a.Longitude
                            FROM [User].[User_Profile] u
                            INNER JOIN [User].[User_Address] a on u.id = a.UserId
                            WHERE u.Id = @UserId", (u, a) =>
                            {
                                u.Id = a.UserId;
                                return u;
                            },
                            new { UserId = userId }, splitOn: "UserId").FirstOrDefault();

I receive this error when running it:

When using the multi-mapping APIs ensure you set the splitOn param if you have keys other than Id“, ”splitOn

My two classes are as follows:

first is the userProfile which im trying to populate

 public class UserProfile
{
    public Int64 UserId { get; set; }

    public string UserName { get; set; }

    public int Age { get; set; }

    public int ProfileStatus { get; set; }

    public Int64 AddressId { get; set; }

    public int Country { get; set; }

    public int State { get; set; }

    public int City { get; set; }

    public decimal Latitude { get; set; }

    public decimal Longitude { get; set; }
}

and this is my User Address Class:

 public class UserAddress
{
    public Int64 Id { get; set; }

    public Int64 UserId { get; set; }

    public int Country { get; set; }

    public int State { get; set; }

    public int Town { get; set; }

    public string PostCode { get; set; }

    public decimal Latitude { get; set; }

    public decimal Longitude { get; set; }
}

I'm not sure what I'm doing wrong as I think I have said to split on the UserId? but clearly that doesn't seem to be the case?

** Update **

Update sql statement with alias

                            SELECT u.Id as [UserId], u.Username as [Username], u.Age as [Age],
                                   u.ProfileStatus as [ProfileStatus], 
                                   a.Id as [AddressId], a.Country as [Country], a.[State] as [State],
                                   a.City as [City], a.Latitude as [Latitude], a.Longitude as [Longitude]
                            FROM [User].[User_Profile] u
                            INNER JOIN [User].[User_Address] a on u.id = a.UserId
                            WHERE u.Id = @UserId", (u, a) =>
                            {
                                u.UserId = a.UserId;
                                return u;
                            },
                            new { UserId = userId }, splitOn: "AddressId").FirstOrDefault();