Checkout page asks for address unnecessarily

I have 2 addresses. One is selected by default when I enter the checkout page.

If I try to update the quantity of my product by entering a number and then HITTING THE ENTER BUTTON, then the page asks me for an address, even though one is selected. When I try to update the quantity using the icon provided, then it updates and works fine.

If I try to update quantity by hitting next, it refreshes and updates the quantity (would be nice to have an alert that says your quantity has been updated).

Hi goloon,

I don't really understood your problem so :
- Can you provide me a link to your web site ?
- Show me screenshots of the problem that you have ?

Thanks