Adding a non-portable Light to the inventory should cause the player to glow
Was selling Nalcarya some stuff, when I'd finished I noticed a blank spot in the player inventory. Clicked around on that spot, and a key (I was carrying) appeared there. Then the lighting for the entire cell (still in the shop) turned a weird shade of yellow. Outside seems normal enough and no other interior cell appears to have been affected, either.
https://dl.dropboxusercontent.com/u/67740160/BUGNalcarya_s_shop_is_yellow_tinged is a savegame with the issue.