FortiInsight monitors endpoint activity in the form of events. It provides automated inspection and alerts against these events in the form of policy and Augmented intelligence (AI) based inspection.
Community Manager
Community Manager
This article indicates the time it takes for the AI to develop a baseline.

AI needs to see two weeks of behaviour from a user to form an effective baseline, and learn what 'normal' behaviour looks like for that user. 

The more data AI gathers, the more detailed a picture it builds, and the behaviour profile of each user becomes more detailed over time.