Ubuntu 16.10 seems unaffected.
$ loginctl show-session 926 c2 927 | egrep Id=\|Leader Id=926 Leader=24113 Id=c2 Leader=4175 Id=927 Leader=24212
$ loginctl show-session c2 927 926 | egrep Id=\|Leader Id=c2 Leader=4175 Id=927 Leader=24212 Id=926 Leader=24113
Ubuntu 16.10 seems unaffected.
$ loginctl show-session 926 c2 927 | egrep Id=\|Leader
Id=926
Leader=24113
Id=c2
Leader=4175
Id=927
Leader=24212
$ loginctl show-session c2 927 926 | egrep Id=\|Leader
Id=c2
Leader=4175
Id=927
Leader=24212
Id=926
Leader=24113