Unity will immediately crash while playing the cutscene if there is a mechanim track in an actor group and set the actor visibility to false.
(But in Editor Play Mode, unity wont crash)
Hello,
This is unfortunately a Unity 5.3.5 bug which has though been fixed in Unity 5.4 and I can confirm it’s working correctly and without an issue in that new version. Being a Unity bug, unfortunately there is not much I can do to fix this or workaround it for Unity v5.3.5. :/