I run a few small chat bots. I can correct specific answers to questions (like the example given) by mapping certain phrases to certain intents, probabilistically. A new model is trained, and deployed. I do it all the time. It takes minutes. No source code changes.

Their model is certainly bigger than mine and while I'm not certain about their process or tech stack, but I'd be willing to bet at even money that their's works vaguely similarly and that they have people looking at usage to see bad responses, updating data, re-running the model.