Since upgrading to 2019 (we're now on 2020.1.x), we have seen a very hard to track down, but persistent bug. When a guest checkout starts, the system will not present the user with shipping address and ship method options and just for extra fun empties their cart. This only seems to happen on a browser where a previous "known user" (previously logged in) has browsed the site and their session has expired. Wondering if anyone else has run into this problem. I have been unsuccessful in creating a 100% repo scenario.