Game Mechanics: Seal of Thoridain cancels player emitted light sources

[Aelzrith]

I recently completed my Coldain Shawl # whatever and was excited for the Seal of Thoridain, but quickly noticed that it canceled all of my player's light sources (Blue Crystal Staff, Tolapumj Robe, Greater Light Stone, Torch, etc.). As soon as I un-equip the seal from my ranged slot, my light sources work. As soon as it is equipped, they are all muted.

I assume this is a bug unless the seal is supposed to.. seal light?

Thx!