PushHandler can't find UI based on request using nginx, spring security

When activating Push, whenever i leave tabs with my application open for longer than a minute, i get the following INFO level log message:

16:57:17 INFO  PushHandler - No UI was found based on data in the request, but a slower lookup based on the AtmosphereResource succeeded. See http://dev.vaadin.com/ticket/14251 for more details.

Ticket 14251 doesn't seem to contain any relevant information for my scenario which is as follows:

The application is a Vaadin Spring application

My UI is annotated with 

@Push(transport=Transport.WEBSOCKET_XHR)

I am using an nginx server configured for push like this:

map $http_connection $upgrade_requested {
    default upgrade;
    ''      close;
}

server {
        listen          9002;
        server_name     localhost;
        root            /;

        location / {
                proxy_set_header X-Forwarded-Host $host;
                proxy_set_header X-Forwarded-Server $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header Host $host:$server_port;

                proxy_cookie_path ~*^/.* /;
                proxy_pass http://127.0.0.1:9003/;
                proxy_redirect off;
        }

        location /vaadinServlet/PUSH {
                proxy_pass http://127.0.0.1:9003;
                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection $upgrade_requested;
        }

This log message appears when i simply leave some tabs open. No pushes are actually happening (at least none triggered by my application logic). This happens in all browsers i've tested it in: Firefox, Chrome, and Safari.
Other than the log message, i have not noticed any problems.

How can i get rid of this log message?
Is this perhaps indicative of some problems which i may not have noticed yet?