Hi,
i posted the issue 1582 some weeks ago. No comment yet. I think it is a
serious issue:
Basically mojarra renderers do not handle empty user input correctly. If
validation fails then the model value is displayed via UiInput.getValue().
Rather the local or submitted value should be displayed. getValue seems to
be broken, in that it cannot return a locavalue of null. That seems to be a
possible situation but instead of retuning null it will evaluate the value
expression.
In my Project I had to fix HtmlBasicRenderer and MenuRenderer to be able to
display an empty user input if the model value is not empty (filled from
earlier submit) and the form is invalid.