UITextField .text attribute always returns an empty string

I'm programming forms for my iOS app, and my UITextFields act strangely :

When the form is in update state (fields are already filled) I can edit and get input text with the .text attribute. But when the form is in insert mode the UITextFields are initially empty and I cannot get the input text with the .text attribute because it always returns an empty string.

I already have relinked the field from the storyboard to my class, and in debug mode my UITextField is not nil.

My textfields are in a static UITableView, so I can see if the update worked scrolling the cell off the screen then scrolling it on.

Does anyone know why is this happening and how to solve the problem?