not sure since when, but
was dropped from inittab. This causes, at least all lxc/lxd, containers to freeze on shutdown. I originally thought this was gentoo-only problem, but now it seems like gentoo containers on other distribution hosts are also affected.
So why was pf:12345:powerwait:/sbin/halt dropped from inittab and can it be added back? AFAIK even in host system, no containers involved, this doesn't cause any issues.
If the guest is systemd based you are still fried as there the inittab doesn't work anymore. (systemd has it's own set of rules .. and issues :-( )