scenario: to show/hide input components via ppr (which are e.g. in a logical area - which is represented by a parent component -> if the area is hidden, it isn't in the dom.)
(the rendered attribute is used here -> the parent component (of the previous mentioned parent component) has to be refreshed to show this area via ppr again)
after hiding the area again this client-side validation source-code remains in place (until the whole form gets refreshed).
-> if a user tries to get to the next view, the client-side validation source-code tries to validate components which aren't in the dom any more.
don't use ppr for this area - trigger ppr for the complete form (i know - it's not nice to do that - it's just a workaround)