The NPC for this quest is supposed to fight you in the oval area where he comes to you and he is just stuck there where he spawned at. I tried abandoning and doing it again and I just spawn more of him. The duel command while on the mount doesn't work either while trying to challenge him.
Please Help.
Thanks !
I didn't find the right solution from the internet.
References:
- https://us.battle.net/forums/en/wow/topic/2075765615945613