Comment 14 for bug 1806969

I could reproduce the bug described.
With the following netplan, it does not trigger the bug:
network:
    ethernets:
        ens3:
            addresses: []
            dhcp4: false
        ens9:
            addresses: []
            dhcp4: false

    bridges:
        broam:
            interfaces:
              - ens3
            addresses:
            - 192.168.105.10/24
            gateway4: 192.168.105.1
            nameservers:
                addresses:
                - 8.8.8.8
        brmaas:
            interfaces:
              - ens9
            addresses:
            - 192.168.106.10/24

    version: 2

When using a bridge on top of a VLAN like in the following netplan configuration, it triggers the bug:
network:
    ethernets:
        ens3:
            addresses: []
            dhcp4: false
        ens9:
            addresses: []
            dhcp4: false
    vlans:
        ens9.1:
            id: 1
            link: ens9
    bridges:
        broam:
            interfaces:
              - ens3
            addresses:
            - 192.168.105.10/24
            gateway4: 192.168.105.1
            nameservers:
                addresses:
                - 8.8.8.8
        brmaas:
            interfaces:
              - ens9.1
            addresses:
            - 192.168.106.10/24

    version: 2

When trying to create the VM, with the following command:
maas root pod compose 1 hostname=juju-1 cores=1 memory=1024 storage=8.0 zone=1 interfaces="eth0:space=oam-space;eth1:space=maas-space"
I get the following error:

Unable to compose machine because: Failed talking to pod: Unable to compose juju-1: error: Failed to start domain juju-1
error: error creating macvtap interface <email address hidden> (52:54:00:00:b9:9d): Device or resource busy

Even if a bridge exists and seems to be recognized by MAAS in the Controllers tab.
I'll attach a sosreport of the MAAS server.