Nginx rate limit WARP users due to same IP?

In my nginx config, I have setup rate limit using http_cf_connecting_ip header:
limit_req_zone $http_cf_connecting_ip zone=site_limit:10m rate=10r/s;

But then I keep receive rate limit from this IP: 104.28.217.184

It look like they are coming from WARP.
So how to I get the real IP of WARP users?