In my last project, I ran into a problem where a CMS-driven slider on Webflow would keep displaying the last slide which has no content, even though it has a conditional visibility set in place to not display that slide if it has no image.
Turns out there is a really simple solution. Just add this code to before </body> tag on the page where you have your slider:
Publish your site and you should be ready to go with a perfectly working CMS slider.