Inconsistency in Repos

[mikehenson]

"May I please ask how you updated the mirrorlist? I am running into exactly the same issue at the moment."

When pacman updates the mirrorlist, it will create 2 new files. 
(be careful, under Arch rolling release. There are more repositories in the pacman.conf that you will want to keep)

Code:

/etc/pacman.conf.pacnew
/etc/pacman.d/mirrorlist.pacnew

Copy them to

/etc/pacman.conf
/etc/pacman.d/mirrorlist

Then force an update of pacman

sudo pacman -Syyu