I'm using magento 2.0.7, and I know is not a magento issue, but when I turn cloudflare on, some of the js doesn't well as they should, for example in the backend I can't save any product, and in frontend, the cart doesn't display the items.
Please disable the following in the CloudFlare dashboard:
- Disable JS minification
- Disable RocketLoader
- Disable Mirage
That should solve the issues, if it doesn't please do come back on here.
Make sure your site is SSL throughout to receive the performance benefits of HTTP/2 through CloudFlare. You can do this by adding a CloudFlare Page Rule.
Check to see if you have Minify HTML on. If you do, the way that the Knockout JS uses comments to add DOM control gets stripped out and none of the back end grids will load as well as other seemingly random JS issues.