A piece of information, or the answer to a question, could exist in the documentation but is not in a format that's easily readable to humans. You ask the AI to add certain information, and it responds with "I already added it". But the AI doesn't "read" documents the way humans read.

For instance, say you need urgent actions from other teams. To this effect you order an AI to write a document and you give it information. The AI produces a document following it's own standard document format with the characteristic AI fluff. But this won't work well, because upon seeing the urgent call for action the teams will rush to understand what they need to do, and they will be greeted by a corporate-pr-sounding document that does not address their urgent needs first and foremost.

Yes, you could tell the AI how to make the document little by little... but at that point you might as well write it manually.