Filters module Requests req/s negative number

[MrYueQ]

Hai. Looking forward to your reply.

question
The request column indicator in the filters module shows a negative number

nginx version

nginx  -V    
nginx version: openresty/1.15.8.1
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-36) (GCC) 
built with OpenSSL 1.1.0j  20 Nov 2018
TLS SNI support enabled
configure arguments: 
...
--add-module=/root/rpmbuild/BUILD/openresty-1.15.8.1/../nginx-module-vts-master

nginx configuration

    server {

        server_name localhost;

        location /status {
            vhost_traffic_status_display;
            vhost_traffic_status_display_format html;
        }
        location ^~ /test {
            return 200 ' test!';
            add_header Content-Type text/plain;
        }
    }


    vhost_traffic_status_filter_max_node 500 uris;
    vhost_traffic_status_filter_by_set_key $uri uris::$server_name;
    # vhost_traffic_status_filter_by_set_key $uri;

    vhost_traffic_status_zone shared:vhost_traffic_status:200m;
    # vhost_traffic_status_filter_by_host on;
    # vhost_traffic_status_filter_check_duplicate on;