Talking to the numerous Vendors in the plaza ( even including the event ones however im not sure they count ), i expected the achievement after i’ve spoken to every known NPC.
The achievement just wont show up! unless there’s secret vendors that count toward the achievement or vendors that have been recently added that i dont know of
Have you talked to the vending machine in the bowling alley?
That NPC is the most overlooked and hidden that counts towards the achievement.
I am having the same probpem and have talked to the vending machines in the alley and in the theater, i cant find anyone else to talk to myself or in online lists and guides.
after almost 2 years of mystery it turns out i was missing Veronica in the cinema that you buy candy from!