On newer systems with systemd205 and higher systemd wants to manage all cgroups excepts those in cpusets. To do this it removes cgroups out of its control and moves the pids to the root cgroup. This causes the cgroups hook to fail when it wants to write the pid to one of the job task files. It also fails to read the accounting information when the job completes.
cgroups hook works as expected on systems running systemd205+