###URGENT### Quantity Value always changes to "1" in Checkout Confirmation page

Hi there,

I just found out that no matter what values are entered into Quantity box that end up only "1" in Checkout Confirmation page. For example, I enter 5 or 100, these numbers are changed to "1" in Checkout Confirmation page. Does anyone know how to fix this bug???
PLEASE HELP!!!

Are you clicking update after you change it?

No, I didn't. Ummm.... Is there a way to prevent visitors clicking "Checkout" button directly after changing quantity???

Thank you for your help!