I can reproduce this at will on embedded alix2d13 running 2.2.6-RELEASE (i386):
lagg0: flags=8843 <up,broadcast,running,simplex,multicast>metric 0 mtu 1500
options=8280b <rxcsum,txcsum,vlan_mtu,wol_ucast,wol_magic,linkstate>ether <removed>inet6 <removed>prefixlen 64 scopeid 0x8
inet <removed>netmask 0xffffff00 broadcast 192.168.17.255
nd6 options=21 <performnud,auto_linklocal>media: Ethernet autoselect
status: active
laggproto lacp lagghash l2,l3,l4
laggport: vr2 flags=1c <active,collecting,distributing>laggport: vr1 flags=1c <active,collecting,distributing>lagg0_vlan9: flags=8803 <up,broadcast,simplex,multicast>metric 0 mtu 1500
ether 00:00:00:00:00:00
inet6 <removed>prefixlen 64 scopeid 0xa
inet <removed>netmask 0xffffff00 broadcast 192.168.18.255
nd6 options=21 <performnud,auto_linklocal>vlan: 0 vlanpcp: 0 parent interface: <none>lagg0_vlan10: flags=8803 <up,broadcast,simplex,multicast>metric 0 mtu 1500
ether 00:00:00:00:00:00
inet6 <removed>prefixlen 64 scopeid 0x9
inet <removed>netmask 0xffffff00 broadcast 192.168.19.255
nd6 options=21 <performnud,auto_linklocal>vlan: 0 vlanpcp: 0 parent interface:</performnud,auto_linklocal></removed></removed></up,broadcast,simplex,multicast></none></performnud,auto_linklocal></removed></removed></up,broadcast,simplex,multicast></active,collecting,distributing></active,collecting,distributing></performnud,auto_linklocal></removed></removed></removed></rxcsum,txcsum,vlan_mtu,wol_ucast,wol_magic,linkstate></up,broadcast,running,simplex,multicast>
the vlanid is 0 and interface is none in such cases. Sadly this happens on every reboot or alteration to the LAGG. This is the first time I'm using such a setup on pfsense, thus I don't know if this ever worked before on this platform.
I left a comment in the related issue: https://redmine.pfsense.org/issues/3976 but I don't think I have permission to reopen the ticket.