Changing rdomain on an interface after the rdomain has already been set openbsd7.0 / 7.1snapshots

Hello,
I came across an issue that once a rdomain is set on a
loopback interface
you cant change it without destroying and re-creating the interace,
while it appears you can change a virtio network interface, is this a
bug or a feature

tobsd# ifconfig lo3 create
tobsd# ifconfig lo3 rdomain 3
tobsd# ifconfig lo3 inet 127.0.0.1/8
tobsd# ifconfig lo3
lo3: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> rdomain 3 mtu 32768
index 5 priority 0 llprio 3
groups: lo
inet6 ::1 prefixlen 128
inet6 fe80::1%lo3 prefixlen 64 scopeid 0x5
inet 127.0.0.1 netmask 0xff000000
tobsd# ifconfig lo3 rdomain 0
ifconfig: SIOCSIFRDOMAIN: Operation not permitted
tobsd# ifconfig


--
Kindest regards,
Tom Smyth.