X-Forwarded-For is not used after update from 2.10 to 2.11 (no replies)

We're behind a load balancer and have our config.ini.php configured:
proxy_client_headers[] = "HTTP_X_FORWARDED_FOR"
proxy_host_headers[] = "HTTP_X_FORWARDED_HOST"

Prior to updating to 2.11, we were getting correct client IPs, but now everything has load balancer IPs.
Our configuration didn't change.

Is there a workaround / patch for this bug?