All ears achievement missing dialogue 483/484

I used a new character and followed a guide, used a checklist for everything but I am still missing one dialogue, checked with every NPC and found nothing.

Is it bugged? Can it be fixed without having to start over?

Assuming the /recheck_achievements chat command doesn't help, you'll likely need to start over.

I've not seen any reports of a bug... if you had posted telling us that you were following a guide, and that Specific NPC Interaction X didn't count for you, then people could weigh in on whether that's a bug or if something had changed in a patch. As-is, nobody knows which guide you were following; nobody knows which specific interaction didn't work for you - nobody can say.

Any time I've done an achievement like that or No Stone Unturned, I've always specifically marked off each step as I completed it and checked to see my progress had updated in-game. It does sound like you were maybe not paying as close attention as you could have done and you just overlooked something by accident. You say you checked every NPC - some interactions are not available permanently, but only for specific stages of a particular quest. So, unfortunately, that doesn't really mean anything other than the achievement's likely bricked for that specific character.

Try record a video from 1 to 484. (also use excel to mark you progress)

You may actually miss one dialogue somewhere