We consider an “Active User” any user who triggered one of your scored events during the engagement period selected (daily, weekly, monthly). We don’t consider an active user someone who triggered ANY event in your product - just the ones you used in creating your scoring profile.
If you would like to consider an active user anyone that logged into your product during that timeframe, then we recommend you add a Login event to your scoring profile (but we recommend weighing it low - like a 1 - so that it doesn't dominate your scoring profile).