Hello there,
So this is about the Quest "The Deserters" a questchain starting at the shady rest inn between Dustwallow Marsh and The Barrens.
Now at this part of the quest you are supposted to go to The Lost Point Tower located at 35,35 and talk to Balon.
You are fighting with him and at about 1/4 of his life he should turn friendly, take in and offer the next quest.
The problem here is he spawns for like 1 second and ends up despawning right away.
You dont need the quest itself to reproduce this as he keeps spawning in a few minutes and despawns right away.