I managed to fix my system. I not sure when or how it happened, but it looks like a few of my KDE packages switched over to the community version (i.e. end in -git) from the extras versions. It might of happened when I installed neochat.
Most of the system was using the extras versions, but I had the following installed:
kcoreaddons-git kdbusaddons-git kwindowsystem-git kcodecs-git kconfig-git kirigami2-git kquickimageeditor-git knotifications-git ki18n-git
Reinstalling the extras versions fixed my issues, i.e. running
pacman -S kcoreaddons kdbusaddons kwindowsystem kcodecs kconfig kirigami2 kquickimageeditor knotifications ki18n
and accepting the replacement of the conflicting packages.