when multiple SSH host key certificates are defined, only one HostCertificate is referenced in sshd_config

I'm not using a cloud provider; I'm installing Ubuntu 20.04 using autoinstall and the bug is triggered during cloud-init with user-data ( cloud-init 22.4.2-0ubuntu0~20.04.1 )

I defined 3 types of SSH host keys and certs in user-data. All 3 keys and certs ended up in /etc/ssh/, but in sshd_config, there is only one HostCertificate line for the RSA key.

user-data excerpt:

#cloud-config
autoinstall:
  version: 1
[...]
  user-data:
    timezone: UTC
    disable_root: false
    ssh_deletekeys: false
    ssh_genkeytypes: [rsa, ecdsa, ed25519]
    ssh_keys:
      rsa_private: |
        [REDACTED]
      rsa_public: |
        [REDACTED]
      rsa_certificate: |
        [REDACTED]
      ecdsa_private: |
        [REDACTED]
      ecdsa_public: |
        [REDACTED]
      ecdsa_certificate: |
        [REDACTED]
      ed25519_private: |
        [REDACTED]
      ed25519_public: |
        [REDACTED]
      ed25519_certificate: |
        [REDACTED]

Result:
in /etc/sshd/sshd_config, only one cert line: HostCertificate /etc/ssh/ssh_host_rsa_key-cert.pub