i dont think this is a bug per se - more likely that your keyring is out-of-sync or borked - the install guide explains that this is a common situation, that you may need to handle manually from time to time

in general, whenever you see an keyring error, upgrade all keyrings before upgrading the rest of the system:

# pacman -Sy archlinux-keyring archlinux32-keyring parabola-keyring

if that does not work, follow the instructions on this wiki article:

https://wiki.parabola.nu/Parabola_Keyring

Captain Obvious who do you think uses this OS? On the bottom of the link it says to file a bug report.

I do not see anywhere that bill-auger has impugned your character, can you please refrain from doing so to him?

Your report does not state anywhere that you have tried the preceding steps in that link. Did you in fact try resetting it? What was the result? Which versions of the respective packages are you using?

it says "If you still have trouble after this procedure, please open a bug report with the errors you see." - the information that you have given, indicates that the only command you have ran was `pacman -Syu`

if you run these commands, it is very unlikely that `pacman -Syu` would fail to work as expected

sudo pacman -Scc
sudo pacman -Syy archlinux-keyring archlinux32-keyring archlinuxarm-keyring parabola-keyring
sudo pacman-key --init
sudo pacman-key --populate archlinux archlinux32 archlinuxarm parabola
sudo pacman-key --refresh-keys

if you still have trouble after running those commands, then there would be something abnormal to look into