WAFV Redirect - stop adding original querystring

Hi,
I have a form with many fields and a captcha element. I have everything configured properly and the form works beautifully. My only issue is I have a customized redirect value if the captcha fails which brings a user back to the original page with the form to show an error and repopulate the fields with the entered data.

The issue is that the original query string is being added to the redirect URL despite my not asking it to be there. Where can I go to turn that feature off?

Ex: my $WAFV_Redirect = "product.php?productid=".$_GET['productid']."#2"

Notice the #2 - this brings the user back to a tab that I have set up. Without it the default is #1 which does not have the form in it and therefore would confuse the user.

But the output when the captcha validation fails is:

product.php?productid=123#2?productid=123

Which returns the user to the default tab and breaks the flow of the page.

So my simple question is: where can I go in the code to turn off the generation of the second querystring (in this case, ?productid=123)?

Thanks!