Slider only show up correctly for logged in users, not for logged out users

When you are seeing differences between logged in and logged out users, that always means a cache plugin problem. Cache plugins are working that way, that you are seeing the not cached version when you are logged in, but the cached version where you are logged out. You should try to clear the cache of your website's caching plugin and if that wouldn't work, search for the name of your cache plugin in our documentation in case you find one specifically for that plugin.