Checkout by Amazon shopping cart bug?

Hi all,

I have my site added on with the payment modules of Google Checkout and Checkout by Amazon. Both work really well in that it integrates easily. HOWEVER, there is a big bug in the files.

For example:

Product A - product page shows only QTY 1 available. Setting in admin are set to not allow out of stock checkout.

When the above is added to cart and a customer puts 2 and updates, the shopping cart says in red at the top of cart, unable to add. So the cart is still showing 2 in the QTY box until its updated. This is where the bug comes in.

If a customer was the click on the Checkout by Amazon or Google Checkout, the according Amazon or Google payment sites will show the price for QTY 2 in cart and complete the process after the info is filled.

IS there a line of code that can stop this from happenning as I really don't want to refund customers too many times as its a negative view by google and amazon.

Thanks