Create 90-refresh-packagekit.hook
file in /etc/pacman.d/hooks/
with the following contents
[Trigger]
Type = Package
Operation = Install
Operation = Upgrade
Target = *
[Action]
Description = Refresh PackageKit
Depends = packagekit
Depends = systemd
When = PostTransaction
Exec = /usr/bin/busctl call --system org.freedesktop.PackageKit /org/freedesktop/PackageKit org.freedesktop.PackageKit StateHasChanged s posttrans