When i try to update any plugins i see a message that the plugin update failed, but the plugin updates do eventually complete. The BPS Pro Setup Wizard is doing the same kind of problem and I see a Cloudflare error page when the Setup Wizard does not appear to complete, but it also does complete eventually.
If you are seeing a Cloudflare error page while doing things like updating plugins or plugin updates are failing (Note: You will see Cloudflare listed in the plugin update failure message) or running the BPS Pro Setup Wizard then that means your Cloudflare option settings are set to apply Cloudflare caching to your WordPress backend Dashboard (wp-admin area). Since Cloudflare should only be caching the frontend of your site and not your backend then you would want to exclude your wp-admin area from being cached by Cloudflare.