just to make sure: changing the sshd configuration fixes your problem as
well? i.e. there is no bug?
Putting ListenAddress $IP rdomain 255 inside sshd_config did the trick,
netstat -nr -f inet was looking at it's default route table which was
255 rtable in this case.
Running sshd_rtable=255 I assume was doing what it's supposed to do, run
within it's configured rtable only, so all running commands using
were confined to that rtable.
I think there is no bug then, I'm sorry for the noise and thank you for
your time and help !