Did some sleuthing for:
Seems I may have found a solution.
First I ran yay to update packages that were waiting to be updated, ignoring appstream-qt.
Then from this source:
https://bbs.archlinux.org/viewtopic.php?id=290264
I ran:
sudo pacman -S appstream-qt && pacman -Suy
That gave no error.
Have no time to do some sanity checks at the moment. Will do that later.