systemd 228 had a bug where it created some files with the sticky bit set. Unfortunately, some of these files were created in /var/lib/systemd (specifically, /var/lib/systemd/timers) and appear to be reasonably long lived (I still have them on my system). The install script should remove the sticky bit from all files in /var/lib/systemd (and should probably remove the executable bit from non-directories as well).