The novelty was doing the work
In month one people try things because trying is interesting. That is a real force and it produces real results, and it is also a battery with a known life. When it runs down, what is left is whatever you built into the actual job. For most organizations that is nothing. The AI lives beside the work instead of inside it, so the moment curiosity fades there is no reason left to open it.
Nobody owns the second mile
The pilot had a champion. Somebody stayed late, answered questions in the channel, and made the whole thing feel like a project worth caring about. Month three is when that person goes back to their real job. The work does not stop needing a champion. It stops having one. I have seen more adoption die on an unstaffed second mile than from any technical problem.
More training is the wrong instinct
The reflex is to schedule another session. Sometimes that helps. Usually it adds to a pile of things people already half remember. What restarts a stalled rollout is smaller and much less satisfying: pick one workflow somebody does every week, rebuild it so the AI is a required step rather than an optional one, and measure the before and after in minutes. One workflow done properly restarts more adoption than a full day of training.
Go slower there, so you can go faster everywhere else.
The honest part
Some of this belongs to us, the people who sell and teach this work. A launch is easy to get excited about. Month three is unglamorous, and it is exactly where the value either shows up or does not. If your rollout is flat right now, that is not a verdict on your team. It is the ordinary shape of the thing. It just needs somebody to own the second mile.
Pour something good. Then go look at one workflow.