Strange/Weird/Baffling Internet Explorer 11 Compatibility Mode Issue with .NET Site

I just resolved a really strange issue with the way my application loads in Internet Explorer 11 when compatibility mode is not on.   It was pointed out by a user and causes behavior such as a "cryptic" string being appended to our site url's and some pages not loading but instead giving a "bad request (invalid url)" error.

Here's a sample of the URL when compatibility is not on:
http://berkley.gettango.com/(F(n8fH3A-2n5nHBGAGMczFOlVwzq5JjV0oC8tRGHiMIxlC_XbJPJZxbpbseaC-w5-Mwg24dU1ZtHXUOYN1SvYUIIql67r5is91kQAb3FPDE1Y20tXNCjALZmSEuAitqo2oSSVlbnX-WQPXd75Pt1c0FnZeEg1G7DhGjCUAErDGP8U1))/dashexec.aspx

and when it's on:
http://berkley.gettango.com/dashexec.aspx

Could anyone explain to me what is going on here?  And better yet,how to fix it so the site loads correctly in IE 11 w/o compatibility turned on.  As a side note, our site uses Telerik Controls.  Not sure if the two are related at all but when compatibility is off many of the controls won't load.