It's not clear from the context, but I would guess that for the one that worked, they gave it several examples in one conversation and eventually it picked up the syntax. The "dozens of hours of training" that didn't work, and can't work, are because ChatGPT doesn't immediately roll all conversations back into the training set. It also specifically told them that its knowledge cutoff of 2021 means OpenAI will not knowingly add this information to the model.