I am not aware of any such requirement.
If that would be the case, any Windows running on a network with IPv4 only connectivity would never be able to receive updates.
When considering to disable IPv6, it would be crucial whether your ISP is providing you with a native dual stack, native IPv4 or native IPv6 connection.
Obviously, disabling IPv6 is not an option in the latter case.
Configuring a DHCPv6 DNS Server may not help.
Most OSs won't use DHCPv6, but SLAAC, learning network details like DNS servers by processing a router's NDP RAs. Your clients would thus use the DNS server IPv6 address as advertised by your router's RA service.
It could be possible that your router's RA service may advertise DNS server IPv6 addresses as configured via DHCPv6, but it may also just use or fall back to advertise its own IPv6 address instead.
Try setting DHCPv6 Server to Off, and correspondingly for your RA Service, setting the M and O flags to Off (indicating that "Managed address configuration" ( Stateful DHCPv6) and "Other configuration" (Stateless DHCPv6) isn't available in your network).
This would have your router instruct devices to exclusively use NDP/SLAAC/RA to join your IPv6 network and hopefully provide no IPv6 address for DNS.
But you should verify that your router's RA service would not advertise its own IPv6 address as DNS server, e.g. by radvdump or rdisc6.