In this case, a "Clerk" next to Tawenu ("Coming to terms" quest) in front of the Vailian Trading Company Headquarters in Queen's Berth.
You can pickpocket him but apart from that he doesn't even say something generic like every other NPC usually does when you click on him. He also doesn't seem to move at all, as he's present at the same spot at night as well.



There's also this Principi priest from earlier related bug reports here and here who's unusually unresponsive as well:

Hail Morpten and well met!

 

Thanks for bringing these issues to our attention! I'll have our QA team investigate these npcs!

 

May Magran bless you!

I have the same bug with NPC Clerk.

From my observation, I think the bug could be reproduced by visiting the Vailian Trading Company in Neketaka in the evening, when the NPC from Duape is scripted to leave but NPC Clerk is not. At that moment, your main character tries speaking to this NPC Clerk. He will not respond anything and get stuck since that incident.

I believe that the bug is caused by inaccurate time script settings on the NPC from Duape and NPC Clerk, or perhaps the NPC Clerk is not made to be clicked on by the player's mouse at all. I suggest testers to evaluate the problem from that.