seo – Google bot is trying to get crawl a URL of another website on the same machine

I am running multiple websites on a Linode VPS server. I use webmin/virtualmin to manage the websites.
Today when I look at Site A’s apache access log, I found that there is a record showing Google bot is trying to crawl a URL that doesn’t exist in Site A, however the URL looks very familiar and later I found out that this URL actually belong to another website that is running on the same machine under same IP address.

Why is this happening? And does this mean there is some misconfiguration on my server?