netifd brings up interfaces set admin-down with "ip link set $I down"

[B]

netifd will immediately and automatically set an interface active/up 
which has been administratively disabled with either the "ip link set $I 
down" or "ifconfig $I down" commands.

Below is an example log after "ip link set eth0.1 down" is used against 
the "lan" configuration/policy. Note that identical behavior is observed 
on a typical ethernet interface (eth0) where there is no intermediate 
switch or VLAN sub interfaces involved.

Sat Sep 11 00:39:59 2021 daemon.notice netifd: VLAN 'eth0.1' link is down
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' has link 
connectivity loss
Sat Sep 11 00:39:59 2021 kern.info kernel: [48844.417075] device eth0 
left promiscuous mode
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (28106): udhcpc: 
received SIGTERM
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is now down
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is disabled
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is enabled
Sat Sep 11 00:39:59 2021 daemon.notice netifd: VLAN 'eth0.1' link is up
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' has link 
connectivity
Sat Sep 11 00:39:59 2021 daemon.notice netifd: Interface 'lan' is 
setting up now
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: 
started, v1.30.1
Sat Sep 11 00:39:59 2021 kern.info kernel: [48845.042493] device eth0 
entered promiscuous mode
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: 
sending discover
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: 
sending select for 192.168.0.148
Sat Sep 11 00:39:59 2021 daemon.notice netifd: lan (29997): udhcpc: 
lease of 192.168.0.148 obtained, lease time 43200
Sat Sep 11 00:40:00 2021 daemon.notice netifd: Interface 'lan' is now up
Sat Sep 11 00:40:01 2021 user.notice firewall: Reloading firewall due to 
ifup of lan (eth0.1)



Before I go into filing bugs or making a case for why this is a problem, 
I should ask: Is this behavior intentional?