Your google-chrome.list file was converted to the DEB822 format but not completely it appears. This part, "deb [arch=amd64] ", should have caused the upgrade script to add the following newline “Architectures: amd64” to the new google-chrome.sources file. This will tell apt to only download lists for the packages built for the amd64 architecture despite having any other architectures (like i386) defined by apt’s config setting “Apt::Architecture”.
So adding “Architectures: amd64” to the google-chrome.sources file and re-updating the package lists should get rid of that warning. You might also want to file a bug.