[CentOS] upgrade to 7.4 ZFS issue

Hi all,

I have a server running 7.3 using the zfs-kmod packages from zfsonlinux.org.
For the update to 7.4, I followed https://github.com/zfsonlinux/zfs/wiki/RHEL-&-CentOS: removal of all zfs - and related packages and installation of 
the zfs-release.7.4.noarch.rpm
Afterwards, yum will find almost all packages from that repository - except for the zfs-0.7.1-1.el7_4.x86_64.rpm itself ("ZFS command line utilities").
However, the package is there, I can get it via wget!
Of course I tried cleaning yum + caches, not removing the zfs packages, removing them before reboot, removing them after booting into  3.10.0-693 - 
all of which makes no difference.

On a fresh installation (aka starting with 7.4), this problem does not occur.


Regardless of any ZFS specifics, what could cause yum to exclude one single package file from an otherwise perfectly accessible repo?

Cheers,
Thomas