The data wasn't wrong, what's wrong is the assumption that the data would be ordered when no order was specified.
That whole blog post could be rewritten into a fairly good demonstration of why assuming an order when an order by is not used is false. Setting it up as multiple temp db files causes a problem is pretty misleading IMO.
"a high severity production incident was caused by adding an additional data file to the tempdb database." -> "adding an additional data file to the tempdb database caused a false assumption in the application to become evident when it caused a high severity production incident."
That's more like it 🙂