Radio button list not doing an asynchronous postback when I expect it to

[Dustin]

I'm working on a website where I need a radiobutton list to do an asynchronous postback.  I have my radajaxmanager set up to have a div that surrounds most of the page update itself when a control in the div postsback.  This works great for all of my controls except the radiobuttonlist.  When one of the radiobuttons is clicked the page does a regular postback instead of the asynchronous one I'm expecting.

A couple of interesting things:
1.  My page does not exhibit this behavior in FireFox (i.e. in FireFox asynchronous postback happens) but does in IE and Chrome.
2.  If I replace the radiobuttonlist with a checkbox list and the user clicks on one of the checkboxes the page does an asynchronous postback.
3. This website is an interface for taking surveys that have been predefined.  Each survey has a collection of sections, each section has a collection of pages, and each page has a collection of questions.  If the radio button list is inside a question it does the regular postback.  If the radiobuttonlist is anywhere above the question level (e.g. on a page or section) it does the asynchronous postback fine.

I have attached a stripped down version of my website that is the bare minimum I've found that can reproduce this problem.

Does anyone know what is going on here?

telerik controls version:  2011 Q1 and previous versions

[Dustin]

I can't attach a zip file.  I'm going to move this to a support ticket