Given a openapi spec containing the following schema:

type: string
oneOf:
  - format: ipv4
  - format: ipv6
example: "2001:db8::"

Running the validate command against it yields this error:

invalid example: input matches more than one oneOf schemas

The error seems to indicate a bug in the ipv4 format because the IPv6 address should only match ipv6 format, not ipv4.

On a side note, it'll be better to change this to anyOf in any case because IPv4 addresses can be contained in IPv6 addresses, but not the other way around.