At the moment I am really unhappy about how Pacman upgrades of kernel packages or any kernel modules work.
The bug is known in Pacman bug tracker, the problems occurred more than once, but there is no official fix :(
The problem is that when updating one of the mentioned packages, the current dkms modules are removed, then the packages get updated and a new mkinitcpio image is built. The building throws error concerning the missing dkms kernel modules which are rebuild after the update, so they are not included in the mkinitcpio image, which can lead to an unbootable system.
Another problem occurred in the latest update the kernel running the dkms builds: The zfs modules needs the spl modules as dependency, so usually spl was built before zfs. This time dkms tried to build zfs first so the build failed.
I am very unhappy and a bit angry with this, because this is not a new issue, but it seems like nobody cares about it. I don’t think this is difficult to make right, so why does this go wrong in Antergos (Arch), but in Ubuntu I never had any problems with kernel modules?