IPv6's equivalent would be DHCPv6 - different protocol, different ports.
Android exclusively uses SLAAC/NDP for IPv6 - it does not support DHCPv6 at all.
If DNS would be involved, it could only be related to Pi-hole -or one of its upstreams, if you opted for some filtering public DNS service- blocking a domain that your client requires to resolve.
The following topic may help in identifying domains involved: