Release Notes for Alpine 3.19.0
Base System
iptables-nft
the /sbin/iptables{,-save,-restore}
symlinks now point to xtables-nft-multi instead of xtables-legacy-multi. this means they use the nftables kernel backend instead of the legacy iptables one.
because mixing backends is not supported, you should reboot your system if you have to use the iptables commands after upgrading.