I do not know if this is intended but it seems building a dark forge and Ganesha with a dark item does not seem to give the experience as before.
Ganesha now has 47xx exp and 543 so it is not even 15% ( and there might be a bonus too)
I equipped 2 dark items but I do not know if they even stack. And my carry also has a dark item.
Maybe this is for the better because it was very easy before to level up dark forge, but still wanted to communicate it.