WP-FS causing no-css flicker on page load

I am experiencing this with and without FS Premium active.

http://www.havanamanor.com

After I clear the cache and view in another browser, I always see the unstyled page/plain text load before the css renders.

If I disable FS the page loads slower but does not flicker.
If I enable FS the page loads faster and flickers.

https://wordpress.org/plugins/wp-fastest-cache/