I've only just starting using this symbol (my relevant stats are about 100 higher than when I first tested offensive symbols and decided they weren't worth using).

I'm seeing immunuties by undead that as far as I can tell (from reading the saved announcement posts on KP) shouldn't be there.

Specifically, the undead on Plane 5 seem to have the same immunity as players do to the mass cast version. The symbol is used, but there is no messaging to indicate any targets have been checked, while from my reading of the post I would have expected them all to be checked but to wake up fairly rapidly.