Google sometimes crawls with currency in URL.. USER CURRENCY mod

Hi,

I have noticed that google is sometimes crawling my sites URL's with the currency parameter included for instance /index.php?currency=AUD&main_page=index or /index.php?currency=MXN&main_page=product_info&products_id=246&number_of_uploads= - every time google tries to crawl one of the URL's with the currency parameter included my site (v1.3.9h) responds with a 302 and forwards google to the correct(?) URL which excludes the currency paramater - for example google tries to crawl /index.php?currency=AUD&main_page=index but then gets forwarded via 302 to ```
/index.php?main_page=index

Is this normal?

The instances of this happening are sporadic. It almost seems like google is making up it's own URL's. 

I don't link to or from any pages with a URL that includes a currency parameter, and my currency sidebox has not been changed or modified in any way. The only currency related addon I have is the [userCurrency](http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=284) mod - which I only use to automatically change a customers currency according to there location AFTER sign up/login (I don't use any other features of this mod i.e the currency pre-selection based on an IP location lookup feature.)

Thanks :smile:

I added a bunch of urls to my robots.txt file as I noticed I was getting penalised for duplicate content.

its not just the currency to worry about either, Google adds the sort filter and a bunch of other stuff.

I added this to robots.txt;

Disallow: /*&sort=*
Disallow: /*&page=*
Disallow: /*?sort=*
Disallow: /*?currency=*
Disallow: /index.php?currency=*
Disallow: /*alpha_filter_id=*
Disallow: /*&disp_order=*
Disallow: /index.php?main_page=index&manufacturers_id=*
Disallow: /review?reviews_id=*
Disallow: review?reviews_id=*