Exception: unknown signature type: PositiveCertification when importing key

./keyringctl import <(gpg --export CFA6AF15E5C74149FC1D8C086D1655C14CE1C13E)
Traceback (most recent call last):
  File "/home/flo/git/arch/archlinux-keyring/./keyringctl", line 8, in <module>
    main()
  File "/home/flo/git/arch/archlinux-keyring/libkeyringctl/cli.py", line 163, in main
    convert(
  File "/home/flo/git/arch/archlinux-keyring/libkeyringctl/keyring.py", line 849, in convert
    convert_certificate(
  File "/home/flo/git/arch/archlinux-keyring/libkeyringctl/keyring.py", line 408, in convert_certificate
    convert_signature_packet(
  File "/home/flo/git/arch/archlinux-keyring/libkeyringctl/keyring.py", line 280, in convert_signature_packet
    convert_subkey_signature_packet(
  File "/home/flo/git/arch/archlinux-keyring/libkeyringctl/keyring.py", line 224, in convert_subkey_signature_packet
    raise Exception(f"unknown signature type: {signature_type}")
Exception: unknown signature type: PositiveCertification

The used key file is here: CFA6AF15E5C74149FC1D8C086D1655C14CE1C13E.gpg