Describe the bug
nflog binary (probably) doesn't support IPv6. See line 179 in external/nflog/nflog.c Hardcoded IPv4 format. IPv6 netlink messages are interpreted as IPv4 messages.

Firewall Logs
See investigation https://forum.xda-developers.com/t/5-0-root-3-5-2-afwall-iptables-firewall-16-may-2021.1957231/page-314#post-85484565 and messages bellow

Smartphone (please complete the following information):

• Device: Oneplus 7t pro
• Android 11,: [LOS 18.1 ]

Additional context
Consider update the nflog utility