P.S. The fact that you see no changes tells me one thing for sure: The truncation and new inserts are NOT happening as you thought.

OK, a few more thoughts:

Have you checked the package execution history for any possible messages or package failures?

Packages that are tested by a user manually hiting the "go" button may...

Just a few thoughts, maybe some too obvious... but:

Have you scheduled the package to run at regular intervals?

Have you verified the truncation on the SQL SVR side is actually happening?

Are...

When one wants no NULLs in the output, is it not faster to put that in the base FROM "derived table", view, or query... the same as mentioned when converting...