netplan set fails silently with wifi access points

The netplan set command fails to add new access-points to a wifi definition. Furthermore, it appears to be overly aggressive in pruning "default" settings with the result that definitions for open access points are stripped from the resulting configuration.

My reproduction case is on a Pi, but I would assume this probably isn't Pi specific:

* Boot a freshly flashed kinetic (or jammy) server image
* Edit /etc/netplan/50-cloud-init.yaml to contain a valid wifi definition for a PSK network, along with an empty definition for an open network (such as one might find in a hotel). For example:

  network:
    version: 2
    ethernets:
      eth0:
        dhcp4: true
        optional: true
    wifis:
      wlan0:
        access-points:
          elmers-ap:
            password: VewyVewySecwet
          hotel-ap: {}
        dhcp4: true
        optional: true

* Use "netplan apply" to apply the configuration and check wpa-supplicant has been configured appropriately:

  $ sudo netplan apply
  $ sudo wpa_cli -i wlan0 list_networks
  network id / ssid / bssid / flags
  0 elmers-ap any
  1 hotel-ap any

* Use "netplan set" to define a new AP with a PSK and check the resulting configuration:

  $ sudo netplan set "wifis.wlan0.access-points.bugs-ap={password:Albuquerque}"
  $ cat /etc/netplan/50-cloud-init.yaml
  network:
    ethernets:
      eth0:
        dhcp4: true
        optional: true
    version: 2
    wifis:
      wlan0:
        access-points:
          elmers-ap:
            password: VewyVewySecwet
        dhcp4: true
        optional: true

Note firstly that the new access point ("bugs-ap") is not present, and secondly that the empty definition for the open access point ("hotel-ap") has been removed. Furthermore, the exit code is 0 so presumably netplan thinks everything went okay.

I've attempted defining the new network by setting the entire access-points sub-tree, but this doesn't work either. Changing the password of existing AP definition with "netplan set" *does* work so I'm assuming this isn't a case of missing functionality, but the addition of new APs does appear broken, and the pruning of open-network definitions is certainly a problem.