google chrome Object [object Object] has no method 'hashchange'

Question

I am coding a single page app and using hash changed to change the views. Every so often I get the following error from chrome (Please note most of my testing is in Chrome, and am seeing the error there. I do test in IE9, FF and Safari, but only to confirm errors, css, and functionality is consistent, so its possible it would happen there. Just have not seen it).

ever once in a while I get

Object [object Object] has no method 'hashchange' and is erroring at

$(window).hashchange( function(){
        switch(location.hash) {

Any ideas what causes it?