bug? in 1.3b2

jQuery v1.2.6:
$('<div>a</div><div>b</div>').not(':eq(1)').length
= 1
jQuery v1.3b2:
$('<div>a</div><div>b</div>').not(':eq(1)').length
= 2
example is a reduction of line 287 in http://jqueryjs.googlecode.com/svn/trunk/plugins/tabs/jquery.tabs.js
:
containers.filter(':eq(' + settings.initial +
')').show().end().not(':eq(' + settings.initial +
')').addClass(settings.hideClass);
Thank you,
-will