form_prep doesn't correctly use already prepped fields in CI 1.7.2

[eluser]Simon Paquet[/eluser]
Is there someone who built a custom prep_for_form (from validation library) or form_prep (from form helper) function so it does not double check html entities?

When I write for instance ' (single quote), the result in the input text is

Code:

'

and in the source code

Code:

'

Looks like one of these is called twice