Nginx trying to create NGX_HTTP_PROXY_TEMP_PATH even when it is overridden via configuration file

[ROMB@…]

configuration slice:

http {
    client_body_temp_path      /var/nginx/client_body_temp;
    proxy_temp_path            /var/nginx/proxy_temp;
    fastcgi_temp_path          /var/nginx/fastcgi_temp;
    uwsgi_temp_path            /var/nginx/uwsgi_temp;
    scgi_temp_path             /var/nginx/scgi_temp;
}

strace log:

open("/var/run/nginx/nginx.pid", O_RDWR|O_CREAT, 0644) = 4
close(4)                                = 0
mkdir("/var/nginx/client_body_temp", 0700) = -1 EEXIST (File exists)
mkdir("/var/nginx/proxy_temp", 0700)    = -1 EEXIST (File exists)
mkdir("/var/nginx/fastcgi_temp", 0700)  = -1 EEXIST (File exists)
mkdir("/var/nginx/uwsgi_temp", 0700)    = -1 EEXIST (File exists)
mkdir("/var/nginx/scgi_temp", 0700)     = -1 EEXIST (File exists)
mkdir("/opt/nginx/proxy_temp", 0700)    = -1 EACCES (Permission denied)
write(3, "2018/05/08 10:17:55 [emerg] 3740"..., 100) = 100
write(2, "nginx: [emerg] mkdir() \"/opt/ngi"..., 78nginx: [emerg] mkdir() "/opt/nginx/proxy_temp" failed (13: Permission denied)
) = 78
brk(NULL)                             = 0xa1a000

So, as you can see according to config and strace, all temp paths already exists and overridden from defaults, but for some unknown reason nginx still trying to create /opt/nginx/proxy_temp

[ROMB@…]

And after looking more at my nginx -V, I do understand that this is probably passenger and not nginx bug. With the high chance it is caused by

static ngx_path_init_t  ngx_http_proxy_temp_path = {
    ngx_string(NGX_HTTP_PROXY_TEMP_PATH), { 1, 2, 0 }
};

But, I'm not an C expert, so live it there for some comments.