XF 1.5 Minify CSS blocks CSS loading

[Alpha1]

I tried to enable Minify CSS under AdminCP >> Options >> Performance but this results in various CSS elements not loading. The entire header (logo, tabs, etc) goes missing.
I am using Redis caching and LiteSpeed Cache. Do you have any idea what is the issue?

 

[Mike]

When you enable this, can you view the CSS output to see what is displayed? (You'd need to view source on a page to see the correct URL to view the CSS the page needs.)