unable to define multiple IPv6 token addresses

[Gary Fowler]

Attempting to migrate an Arch linux config to Ubuntu server.

Currently defined, and working, in Arch using systemd/network/eth0.network syntax/configuration.

IPv6Token=static:::31
IPv6Token=static:::32
IPv6Token=static:::33

With netplan, I'm only able to get one address working.

Attempted the following commands with netplan:

eth0:
ipv6-address-token: ::31
# works

eth0:
ipv6-address-token: [ ::31, ::32 ]
# fails

eth0:
ipv6-address-token: [ "::31", "::32" ]
# fails

eth0:
ipv6-address-token:
  - ::31
  - ::32
# fails

eth0:
ipv6-address-token: ::31 ::32
# fails

eth0:
ipv6-address-token: ::31, ::32
# fails

eth0:
ipv6-address-token: ::31
ipv6-address-token: ::32
## Only the last entry works..