Juju fails to validate the charm OS series when --switch is used

Hello OpenStack Team!

We realized this weekend that Vault 1.8/stable charm no longer supports Focal track.

$ juju info --series focal vault
name: vault
publisher: OpenStack Charmers
summary: a tool for managing secrets
description: |
  Vault secures, stores, and tightly controls access to
  tokens, passwords, certificates, API keys, and other
  secrets in modern computing. Vault handles leasing, key
  revocation, key rolling, and auditing. Through a unified
  API, users can access an encrypted Key/Value store and
  network encryption-as-a-service, or generate AWS IAM/STS
  credentials, SQL/NoSQL databases, X.509 certificates,
  SSH credentials, and more.
store-url: https://charmhub.io/vault
charm-id: u3vtXfBTJwhYCwwvkzCs0YqdCfsOBMdO
supports: jammy
tags: security
subordinate: false
relations:
  provides:
    certificates: tls-certificates
    nrpe-external-master: nrpe-external-master
    secrets: vault-kv
  requires:
    db: pgsql
    etcd: etcd
    ha: hacluster
    lb-provider: loadbalancer
    shared-db: mysql-shared
channels: |
  1.8/stable: –
  1.8/candidate: –
  1.8/beta: –
  1.8/edge: –
  latest/stable: –
  latest/candidate: –
  latest/beta: –
  latest/edge: 9bf2a4c 2022-08-02 (79) 46MB
  1.7/stable: ba1ffbf 2023-08-14 (178) 47MB
  1.7/candidate: ↑
  1.7/beta: ↑
  1.7/edge: ↑
  1.6/stable: 1648b97 2023-09-14 (182) 42MB
  1.6/candidate: ↑
  1.6/beta: ↑
  1.6/edge: ↑
  1.5/stable: 24b65b7 2023-09-14 (181) 42MB
  1.5/candidate: ↑
  1.5/beta: ↑
  1.5/edge: ↑

I have a Vault HA cluster on Focal/Yoga that was upgraded to 1.8 a few months ago and now it is not possible to receive refreshed charms:

$ juju status vault
Model Controller Cloud/Region Version SLA Timestamp
vstack home-lab-default Home-Lab/default 2.9.37 unsupported 10:01:24-07:00

App Version Status Scale Charm Channel Rev Exposed Message
lds-client-focal active 3 landscape-client stable 49 no System successfully registered
vault 1.8.8 active 3 vault 1.8/stable 179 no Unit is ready (active: true, mlock: disabled)
vault-hacluster active 3 hacluster 2.0.3/stable 113 no Unit is ready and clustered
vault-mysql-router 8.0.34 active 3 mysql-router 8.0/stable 90 no Unit is ready

Unit Workload Agent Machine Public address Ports Message
vault/4* active idle 0/lxd/6 10.1.15.134 8200/tcp Unit is ready (active: true, mlock: disabled)
  lds-client-focal/28 active idle 10.1.15.134 System successfully registered
  vault-hacluster/4* active idle 10.1.15.134 Unit is ready and clustered
  vault-mysql-router/4* active idle 10.1.15.134 Unit is ready
vault/7 active idle 1/lxd/10 10.1.15.143 8200/tcp Unit is ready (active: false, mlock: disabled)
  lds-client-focal/814 active idle 10.1.15.143 System successfully registered
  vault-hacluster/7 active idle 10.1.15.143 Unit is ready and clustered
  vault-mysql-router/7 active idle 10.1.15.143 Unit is ready
vault/8 active idle 101/lxd/9 10.1.15.160 8200/tcp Unit is ready (active: false, mlock: disabled)
  lds-client-focal/821 active idle 10.1.15.160 System successfully registered
  vault-hacluster/8 active idle 10.1.15.160 Unit is ready and clustered
  vault-mysql-router/8 active idle 10.1.15.160 Unit is ready

Machine State Address Inst id Series AZ Message
0 started 10.1.8.31 os-controller-1 focal default Deployed
0/lxd/6 started 10.1.15.134 juju-b096f0-0-lxd-6 focal default Container started
1 started 10.1.8.33 os-controller-3 focal default Deployed
1/lxd/10 started 10.1.15.143 juju-b096f0-1-lxd-10 focal default Container started
101 started 10.1.8.32 os-controller-2 focal default Deployed
101/lxd/9 started 10.1.15.160 juju-b096f0-101-lxd-9 focal default Container started

Would it be possible to re-add Focal to 1.8/stable channel please?

Thanks much,
Alan