If the preview window is different from the actual front-end page, then it is very likely that the styles have been cached.
Make sure to:
– Clear any cache you have (assets, page, minify etc..)
– Clear the browser cache
– Cloudflare or any equivalent
– Reload the page with CTRL + SHIFT + R to enforce reloading of assets
Unfortunately caching is independent from the plugin, it cannot control that. It does send a query string change and request, but then it’s up to the caching solutions to actually clear their cache data.