[eluser]jedd[/eluser]
The trick is to never need to explain it.
When you see output that doesn't match what you believe to be the input, the source of the problem is very easy to identify.
(Hint - you modify the source code to see if the change reflects in the page-source as rendered by your browser - if it does not, you've proven it out.)
This is pretty basic programming theory - it's not even PHP, let alone CI, specific.
These forums are littered with threads containing the emphatic words
'I'm very sure ...'
They are usually followed, some messages later, with the phrase
'Oh, yeah, I forgot that I'd ...'