Invalid added column

CREATE TABLE Customers (
        ID INT IDENTITY NOT NULL,
        FirstName NVARCHAR(50) NOT NULL,
        LastName NVARCHAR(50) NOT NULL,
        Manager NVARCHAR(100) NULL
        CONSTRAINT PK_Customers PRIMARY KEY (ID)
        )
GO

ALTER TABLE Customers
ADD CustomerDate DATE NULL
GO

USE SoftUni
GO
CREATE PROCEDURE usp_NewCustomer
        @FirstName NVARCHAR(50),
        @LastName NVARCHAR(50),
        @Manager NVARCHAR(100),
        @CustomerDate DATE
AS
        INSERT INTO Customers
                (FirstName, LastName, Manager, CustomerDate) VALUES --INVALID COLUMN NAME DATE?!
                (@FirstName, @LastName, @Manager, GETDATE())
GO

--Recreate the table:

DROP TABLE Customers

CREATE TABLE Customers (
        ID INT IDENTITY NOT NULL,
        FirstName NVARCHAR(50) NOT NULL,
        LastName NVARCHAR(50) NOT NULL,
        Manager NVARCHAR(100) NULL,
        CustomerDate DATE NULL
        CONSTRAINT PK_Customers PRIMARY KEY (ID)
        )
GO

USE SoftUni
GO
ALTER PROCEDURE usp_NewCustomer
        @FirstName NVARCHAR(50),
        @LastName NVARCHAR(50),
        @Manager NVARCHAR(100),
        @CustomerDate DATE
AS
        INSERT INTO Customers
                (FirstName, LastName, Manager, CustomerDate) VALUES --Now Date is valid, why?
                (@FirstName, @LastName, @Manager, GETDATE())
GO