Slitherine

I'm playing a custom wizard, 6 Nature/3 Life + Channeler. As expected, combat spells on the Arcanus plane are at base mana cost no matter what distance from my fortress. However, on the other plane I'm not receiving that discount and the spells are costing 3x the mana--is this working as intended?

I have no memory of channeler not working between planes in the original game (but then, I have no concrete memory of it working, either).