Just an additional note (if it hasn't already been mentioned). This same issue also caused a problem with the "Register & Checkout" button, where the user is redirected to MYSITE/shop/user, but receives "0 - Invalid address" message.
The shopfunctionsf.php patch also fixed this issue for me. I do believe I had to update to Virtuemart 3.0.14 for the issue to be sorted too.