Given the HTML:

123<div id="foo">Foo</div>456

The code

$('#foo').replaceWith('Bar');

Previously (in 1.3.2) would result in: 123Bar456

Now you get: 123456

The problem is that $(value).detach() is being used internally, which treats the string 'Bar' as a selector instead of a text node. Since it doesn't find anything, the node is just removed.