Must be a IE10 thing. No other major browsers display such as warning. IE has always been a bitch to deal with.
Most likely caused by this line in templates/base/_header.html
<meta http-equiv="X-UA-Compatible" content="IE=Edge" />
However i am guessing some setting in your browser. Many are already using IE10 as it is the default browser in windows 8, and i have not seen anyone report this issue yet.
That line is intended to tell IE not to use compatibility mode. It was added to newer versions of dolphin due to issues with IE8 and 9 and people not realizing what mode they set their browser to. It may not be possible to get the site to work without problems on all versions of IE. If you must support IE10. Then try removing that line. But it may break older versions of IE.
