I too have this issue, I have gone back to earlier saves to fix this and kill all leaders again. After all the leaders are dead he will talk to me and leave the area. I take the portal to the grove walk in talk to Zevlor and head to the inner circle. After the scene with Kagha he turns into a bear and stands in front of the stairs of the inner circle. From this point on he can not be talked to. I have tried porting to different way points before going to the grove. I have tried reloading old save/killing leaders again. No dice. If you go to camp from this point the celebration scene will trigger but he is still in bear form unable to be talked to. From this point forward two things happen. Either you can't talk to anyone from that point forwards or the morning after he is still a bear and you still can't talk to him.
In the journal the task shows completed and to talk to Rath for a reward.
In this scenario Kagha was saved and the dark druid destroyed. I hope this helps.
This is also the first time I let Kagha live.
I have no mods and I have been past this scene before patch 7.
Last edited by Tameelah; 21/04/22 11:39 AM.