Not possible to use certain start addresses in whereabouts IPv6 range [Backport 4.12]

If we use a macvlan with the configuration...
spec:
  config: '{ "cniVersion": "0.3.1", "name": "ran-bh-macvlan-test", "plugins": [ {"type": "macvlan","master": "vlan306", "mode": "bridge", "ipam": { "type": "whereabouts", "range": "2001:1b74:480:603d:0304:0403:000:0000-2001:1b74:480:603d:0304:0403:0000:0004/64","gateway": "2001:1b74:480:603d::1" } } ]}'

there is an error creating the pod:

  Warning  FailedCreatePodSandBox  17s (x3 over 55s)  kubelet            (combined from similar events): Failed to create pod sandbox: rpc error: code = Unknown desc = failed to create pod network sandbox k8s_test31_test-ecoloma-01_a593bd0a-83e7-4d31-857e-0c31491e849e_0(5cf36bd99ffa532fd34735e68caecfbc69d820ba6cb04e348c9f9f168498022f): error adding pod test-ecoloma-01_test31 to CNI network "multus-cni-network": [test-ecoloma-01/test31:ran-bh-macvlan-test]: error adding container to network "ran-bh-macvlan-test": Error at storage engine: OverlappingRangeIPReservation.whereabouts.cni.cncf.io "2001-1b74-480-603d-304-403--" is invalid: metadata.name: Invalid value: "2001-1b74-480-603d-304-403--": a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')
  
  
If we change the start IP address to 2001:1b74:480:603d:0304:0403:000:0001, it works ok ok.

4.13

Always reproducible

1. See description of problem.

Unable to create pod

IP range should be valid and pod should get created