Hi Cloudzio,
Understood. You may want to clear out those saved favorites from your user application cache. Before you begin, make sure you've got a good backup of your data: How to back up your Mac
Then you'll want to quit Safari, open up the Finder and select on the Go menu > Go to Folder. Type in this exactly without any additional spaces: ~/Library/Safari/Favicon Cache/
Once loaded, you should see a folder named 'favicons' and documents, select all and move them to the trash. After that, restart your Mac: How to turn your Mac on or off This will likely remove all of the favorite icons, but they will reload and when they do, they should be correctly displayed.
If you continue to have issues, we'd Contact Apple Support
Take care!