Maybe I missed it, but is Web Form Builder built for certain API version of Google Checkout?

Within Google Checkout under Integration you select the API version.
"If you are using a third-party shopping cart, please consult your shopping cart provider on which API version to use. If you are unable to confirm which version to use with your shopping cart provider, using Version 2.0 is safest. "

By default it uses 2.0. Just wanted to make sure I had Google Checkout set to correct version for Web Form Builder.

The form submission has been working flawless, but the Google Payment piece has sometimes caused isses. When the users click on the Google Checkout Button it is sometimes taking them back to a blank form or I've had two people say they receive the following error...

Your form could not be submitted for the following reason(s):
• Error parsing XML; message from parser is: Invalid value for body of continue-shopping-url in checkout-shopping-cart/checkout-flow-support/merchant-checkout-flow-support: URL contains illegal characters

This is a live site, so I would have to create sandbox version if someone needs to look at things. Hoping that the Google API version can be confirmed and someone might have experienced this issue or have helpful pointers.

I would open a support topic.
https://www.coffeecup.com/help/myroom/opentopic/