ToME: the Tales of Maj'Eyal

To be honest, I don't know if this is a bug. In the Orc DLC, after clearing out the Primal Forest (including the upper level), the lower level with the forest will provide an endless number of Bosses, Uniques, and Rares, all with the expected loot. All you have to do is move back and forth and a tree will awaken. However, in spite of accumulating tons of unique items, I noticed I never got any experience for the kills.

assuming thats how it works in the sludgenest as well, i would say "working as intended."