Commented Issue: AjaxFileUpload assumes no query strings already exist in page URL on postback [27149]

When AjaxFileUpload post back it takes your page URL and appends onto the end of it it's own query strings (contextkey and guid). This works fine if your page URL doesn't already contain any query strings but if it does then you end up with a URL that contains two question marks which then corrupts your own final query string value and this in turn stops the upload from working.
Comments: Has anyone else noticed a recurrence of this issue with the latest builds (2013)? I have the AjaxFileUpload inside of a usercontrol and the querystring is not recognized. The AsyncFileUpload works fine but does not allow for multiple files.