kern/50717: It's not possible to utilise a gateway in another subnet

[venture37%geeklan.co.uk@localhost]

>Number:         50717
>Category:       kern
>Synopsis:       It's not possible to utilise a gateway in another subnet
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          support
>Submitter-Id:   net
>Arrival-Date:   Tue Jan 26 14:25:00 +0000 2016
>Originator:     Sevan Janiyan
>Release:        HEAD
>Organization:
>Environment:
NetBSD  7.99.26 NetBSD 7.99.26 (GENERIC.201601251230Z) #0: Mon Jan 25 13:29:38 UTC 2016  builds%b45.netbsd.org@localhost:/home/builds/ab/HEAD/amd64/201601251230Z-obj/home/source/ab/HEAD/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
I'm running NetBSD as a bhyve guest in a scenario where ISP assigns IP addresses with a /32 mask, the administrator assigns these addresses to guests and uses the same gatway IP address as used by the host (guests are bridged to the same ethernet interface as the host).

Following the steps outlined in the NetBSD FAQ, it's not possible to get this working
http://www.netbsd.org/docs/network/#nonsubnetgateway

assuming the IP address assigned to guest is 1.2.3.4 and the default gateway to use is 10.0.0.1

running route add -host 10.0.0.1 -link vioif0 -iface adds a route, but then console is filled with arp notifications 
e0:2f:6d:00:00:1a tried to overwrite permanent arp info for 10.0.0.1
It is not possible to ping 10.0.0.1 at this stage.

>How-To-Repeat:
Assign an IP address to ethernet interface
Setup a route to a gateway in another subnet
try to ping gateway IP address
>Fix: