Using Google Cloud to host our Odoo 10 instance and the HTTPS request is terminated at the Google Load Balancer. All transactions are being redirected / balanced on port 443 outbound and 8069 inbound. 

added proxy_mode = True and web.base.url.freeze = True on the configuration to ensure that we are staying on https. All transactions seem to be working ok till we get to the eCommerce shopping cart workflow. 

When we go from Address Confirmation (/shop/confirm_order) to Payment Options (/shop/payment), the protocol shifts to HTTP. Looks like this is hardcoded somewhere in the code. When I change the protocol to HTTPS on the browser, the screen works and then the next screen (/shop/payment/validate) goes back to HTTP and invalidates the session. 

Any idea where this protocol is hardcoded?

Regards,

Vishal.