Creating duplicate temp tables inside nested stored procedures

Question

Here is the situation:

Procedure 1 creates a temp table (#MYTABLE) and calls Procedure 2. Procedure 2 also tries to create #MYTABLE, with different columns. When Procedure 2 tries to insert data into #MYTABLE, an error happens complaining "Invalid column name". I have two questions about this:

1) Shouldn't the system complain when #MYTABLE is created inside Procedure 2? I understand why it can't object at compilation time, but at runtime I would expect an error.

2) Given that it doesn't complain about the creation, and in fact when you SELECT from #MYTABLE inside Procedure 2, you see the new column, why does it complain about the INSERT?

Below is the code. Uncommenting either INSERT statement will get the error.

(I know a lot of ways to fix this situation, so I don't need responses about that. I just want to understand what's happening.)

IF OBJECT_ID(N'dbo.MYPROC1', N'P') IS NOT NULL
    DROP PROCEDURE dbo.MYPROC1;
GO

CREATE PROCEDURE dbo.MYPROC1
AS
    CREATE TABLE dbo.#MYTABLE ( Name VARCHAR(256) );

    SELECT
        'DO NOTHING 1' AS TABLENAME;

    EXEC dbo.MYPROC2;

GO

IF OBJECT_ID(N'dbo.MYPROC2', N'P') IS NOT NULL
    DROP PROCEDURE dbo.MYPROC2;
GO

CREATE PROCEDURE dbo.MYPROC2
AS
    SELECT
        'INSIDE PROC 2 BEFOREHAND' AS TABLENAME
       ,*
    FROM
        dbo.#MYTABLE;

    CREATE TABLE dbo.#MYTABLE
        (
         Name VARCHAR(256)
        ,LastName VARCHAR(256)
        );

    --INSERT  INTO dbo.#MYTABLE
    --        ( Name, LastName )
    --        SELECT
    --            'BARACK'
    --           ,'OBAMA';

    SELECT
        'INSIDE PROC 2 AFTERWARDS' AS TABLENAME
       ,*
    FROM
        dbo.#MYTABLE;

    --INSERT  INTO dbo.#MYTABLE
    --        ( Name, LastName )
    --        SELECT
    --            'BARACK'
    --           ,'OBAMA';

    SELECT
        'DO NOTHING 2' AS TABLENAME;

GO

EXEC MYPROC1;

Answer 1

From the Create Table documentation:

A local temporary table created within a stored procedure or trigger can have the same name as a temporary table that was created before the stored procedure or trigger is called. However, if a query references a temporary table and two temporary tables with the same name exist at that time, it is not defined which table the query is resolved against. Nested stored procedures can also create temporary tables with the same name as a temporary table that was created by the stored procedure that called it. However, for modifications to resolve to the table that was created in the nested procedure, the table must have the same structure, with the same column names, as the table created in the calling procedure.