If the meeting is scheduled in your Calendar Events from ex. 08:00-09:30, the Busylight will stay red for the entire duration of the Calendar Event, unless you manually change your status in Teams. If you leave your meeting early, the busylight will continue to display your presence as being in a meeting. This happens because Microsoft Teams mirrors your Outlook calendar and since the meeting isn't over yet (at least not for everyone), your busylight will continue to stay busy.