So I have two forms, both have a file type input field and I tried
$(\'.inputfield1\').change(function(){
var file = $(this).val();
$(\'.inputfield2\')
I know it is a late answer, but I had a similar problem that I just figured out today.
What I did was move the File input to the new location after deleting the current one in the other location. By moving the element, everything stayed intact on all my tests.
$('.inputfield1').change(function() {
$('.otherinputfield').remove();
$('#newform').append($(this));
});