favicons do not get updated

Hello. This morning I deleted all my history in Safari, and to my surprise all the favicons in my bookmarks are not the generic blue globe. So I became okay with the idea that as I surf the web to my favorite sites, the favicons will get updated to the specific icon for that web page. But sometimes that does not happen either. For example, as I went to a google website, all the icons for google websites were updated to the google icon. But I went to the main page of amazon dot com, and the favicon did not get updated in my bookmarks. However, I can see the favicon for amazon is there in ~/Library/Safari/Favicon Cache/favicons. How can I fix this problem? Thanks.