Cloudflare or plugins breaking my Discourse instance?

[schleifer (Andrew Schleifer)]

How are you using Cloudflare, specifically?

Here is a very relevant topic:

Full site CDN acceleration for Discourse

Fastly , CloudFlare and a few other CDNs offer a mode where they accelerate dynamic content. In a nutshell you point your domain IP address at the CDN and the CDN will intelligently decide how to deal with the request. Static content can be easily served from cache Dynamic content can be routed to the site. This provides some advantages over only shipping static assets which is covered in the CDN howto. You can elect for “shielding” that protects your site from traffic spikes. Dynamic cont…

Have you followed the three steps given there?