How to fix this bug. I was able to fix this by hiring a horde rogue (paid him 62g!) to come to SW and kill the robot then Tyrion. After about 5 minutes Tyrion respawned with quest available and I’ve been able to complete the full questline on two alts. Basically you need to hard reset this NPC since Blizzard won’t do it.
Confirmed this is also bugged on Earthfury.
Bugged 07/27/2020 on Westfall server, too. I’m level 33 mage. Will wait until server reset day. Submitted bug as well.