In the Bastion of Flames, possibly because of an update made a while ago to pets (disallowing them to travel through lava), Conjurors cannot use their pets until the last mob. The pets simply won't move or attack, even the caster pet. The last mob, however, is still attackable to the pets.
Yup, same thing happened to me as a necro. My pet just stared stupidly at the 4 named djinns. Fortunately he was able to attack Djarn
Tried this again last night, and the same problem exists. However, on the last mob, my pet seemed to get lost for about 30 seconds before actually finding the guy. I've noticed that elsewhere though, where my pet runs far away before returning to actually help.
