Last update was ~20 hours ago: $ rsync --list-only rsync://rsync.gentoo.org/gentoo-portage/metadata/ | grep timestamp -rw-r--r-- 29 2018/05/21 01:39:00 timestamp -rw-r--r-- 32 2018/05/21 21:30:01 timestamp.chk -rw-r--r-- 78 2018/05/21 01:39:00 timestamp.commit -rw-r--r-- 43 2018/05/21 01:39:00 timestamp.x
The core reason has been fixed. Just have to wait on mirror propagation at this point.