IPv6 Port 161,162 on Azure VM, Blocked by Azure?

VM does not receive traffic on port 161,162 over IPv6, IPv4 traffic for port 160-163 is fine, also IPv6 160 and 163 is fine. Why is IPv6 discriminated?
(Same behavior on both TCP and UDP)

The main issue is seen on both a Windows and Linux VM, firewalls in VMs verified (and for tcpdump out of scope)

Details with packet dumps and commands to test at https://serverfault.com/questions/1190314/azure-vm-firewalling-does-not-allow-port-161-162-snmp-over-ipv6