At first I thought it might just be something wrong with https://repo.manjaro.org (I always check here first to make sure my mirror list is fully up-to-date before doing updates), but using pacman-mirrors also give the same result.
Than the obvious thing to do is wait for them to become synchronised again. I don’t know if there is, but it might, and generally is as far as I know, because new updates are being pushed.
You need not tell me that, I’ve been around here a very long time and it’s what I normally do, but in this case, all mirrors being out of date yesterday and again so far today - it’s unusual.