get_public_suffix("ns1.linode.com") returns "ns1.linode.com"

This seems to be a bug, because "linode.com" is not on the public suffix list. Several subdomains and related domains are, but not linode.com:

// Linode : https://linode.com
// Submitted by
members.linode.com
*.nodebalancer.linode.com
*.linodeobjects.com
ip.linodeusercontent.com

I would expect get_public_suffix("ns1.linode.com") to return "linode.com"