I'm having a similar problem, not quite the same but the Collapsible doesn't seem to work right when generated with Knockout.
I've put together a fiddle here
http://jsfiddle.net/5yA6G/1/The first section is static and works fine.
The second is generated, and even with calling .collapsible after binding, the header is showing up twice, where it doesn't do that in the statically defined collapsible.