I have now killed 3 worlds bosses on torment and I am not receiving credit towards the seasonal journey.
You don’t get credit if you teleport out as soon as the boss dies, you have to stay there until you get the pop up windows telling you that you received the whispers/seasonal progress credit. It can take up to 30-45 sec.
I have stayed there for over 5 minutes every time.
Having same issue. Stuck at 13 of 15 bosses. I have never stayed long after it ended previously. Usually collect loot, emote Cheer, and then leave. Finished the world boss about 6 times now and still shows 13/15.