The first thing to do is to identify which style sheet is failing. If you can share the URL of the stylesheet and explain which styles on the page are rendered incorrectly that can help us track this down. It may be your style sheet has a parsing error that Cloudflare’s minification does not understand, or there is a bug in the minification itself.
Thanks for the suggestion about identifying which style sheet it is, I’ve been so busy, I haven’t had time to debug it, I’ve just reverted to letting w3tc do the work. I did a speed test on webpagetest.org and it’s my main style sheet that will not load. I’ll have to get back to looking for the solution at a later date