as far as what i have found about this bug it has been here since the age of sorcery and only has gotten worse since the age of war in my case things that are now/have been invisible are Black Yeti, King Rhino, Rockslide, Avalanche, snake men brutes, camels, yetis, elephants, greater yakkiths, the lion king on swagger rock, elephant boss, and all you see are its eyes now if it has eyes. sadly you may be better off just finding a new game to play since the age of sorcery the game has been going down the drain with no real fixes to anything but fast fixes to the shop so you can buy things that may bug/brake your game. i know i am looking for a new game. and only go to the Forums to hope something gets fixed but hope is the first step on the road to disappointment.