Not a bug, but it seems to have to way to use .val()!

Variable as a link

var sVar = $('#Item').val(); Will set a link to Item value

$('#Item').val('Text'); sVar will take the value 'Text'

Independant Variable should be set like this

var sVar;

sVar = $('#Item').val();

$('#Item').val('Text'); Now sVar will keep the old value

Tested on Firefox