sshd doesn't disconnect for 30+ minutes after the TCP connection is closed ungracefully

[Yuri]

Windows system connects to FreeBSD through ssh and then this connection 
dies because of WiFi or VPN issues.

FreeBSD still has the sshd process alive for this connection for 30+ 
minutes.

TCP keepalive is enabled on the FreeBSD host:

$ sysctl net.inet.tcp.always_keepalive
net.inet.tcp.always_keepalive: 1

Shouldn't TCP keepalive kill this sshd process after 3-4 minutes because 
this connection isn't alive?


Yuri