Sql-server – Validation warning in Data Flow Task in the SSIS

I am trying to load data into my DimEmployee table using the Data Flow Task. However, I noticed when I run the SSIS, the DimEmployee filled with 4 records out of 9 and also the EmpKey starts counting from -1 then generates random numbers after that! Also I have a warning associated when running the package:

Warning 1 Validation warning. Data Flow Task:
{DC10B0CA-A6DE-4036-98A6-496811C09D4A}: Truncation may occur due to
inserting data from data flow column "TitleOfCourtesy" with a length
of 25 to database column "Title" with a length of 8.
DimEmployee.dtsx 0 0

I created a procedure in my SSMS which supposes to fill the nulls in the columns by 'UNKNOWN'

USE [NorthWindDW]
GO


SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE [dbo].[Insert_New_Employee] 

AS
BEGIN

    SET NOCOUNT ON;
    IF NOT EXISTS 
    (
        SELECT * FROM [dbo].DimEmployee
        WHERE EmpKey = -1
    )

    BEGIN
    SET IDENTITY_INSERT [dbo].[DimEmployee] ON 
    INSERT [dbo].[DimEmployee] (EmpKey, EmpId,Title, EmpFirstName, EmpLastName, HireDate,Country, StoreCode, Telephone,JobTitle) VALUES
    (-1,-1,'UNKNOWN','UNKNOWN','UNKNOWN','1900-01-01', 'UNKNOWN','UNKNOWN', 'UNKNOWN','UNKNOWN');
    SET IDENTITY_INSERT [dbo].[DimEmployee] OFF
    END
END

GO

This is my DimEmployee Table

Create Table [dbo].[DimEmployee]
(EmpKey        INT IDENTITY NOT NULL,
EmpId          INT NOT NULL,
EmpFirstName   NVARCHAR(50) NOT NULL,
EmpLastName    NVARCHAR(50) NOT NULL,
Title          NVARCHAR(8) NOT NULL,
HireDate       DATE        NOT NULL,
Country        NVARCHAR(50) NOT NULL,
StoreCity      NVARCHAR(50) NOT NULL,
Telephone      NVARCHAR(25) NOT NULL,
JobTitle       NVARCHAR(50) NOT NULL);
Go