Redis is seeing legitimate connections as attacks - possibly due to reverse proxy?

I'm running Redis for use with Rails and Action Cable. These all sit behind an Nginx reverse proxy. Currently whenever Redis is connected to, I get

# Possible SECURITY ATTACK detected. It looks like somebody is sending POST or Host: commands to Redis. This is likely due to an attacker attempting to use Cross Protocol Scripting to compromise your Redis instance. Connection aborted.

Is it possible the Nginx setup is causing this? Here is the config if so:

server {
       server_name "###";
                                                                                                                                                                                    location / {                                                                                                                                                                          proxy_pass http://127.0.0.1:3000;                                                                                                                                            proxy_set_header  X-Forwarded-Proto $scheme;
                proxy_set_header  X-Forwarded-Ssl on;                                                                                                                                        proxy_set_header  X-Forwarded-Port $server_port;
                proxy_set_header  X-Forwarded-Host $host;
        }
        location /cable {                                                                                                                                                                    proxy_pass http://127.0.0.1:6379;
                proxy_set_header  X-Forwarded-Proto $scheme;                                                                                                                                 proxy_set_header  X-Forwarded-Ssl on;                                                                                                                                        proxy_set_header  X-Forwarded-Port $server_port;                                                                                                                             proxy_set_header  X-Forwarded-Host $host;
        }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/###/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/###/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}server {
    if ($host = ###) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


       listen 80;
       server_name "###";
    return 404; # managed by Certbot


}