how does teams last seen work?

Hello Mounika Badugu,

Thank you for posting in the Microsoft community!

Based on the information you have shared with us I understand you would like to know how last seen works in teams.

The last seen is displayed on a user when the user has not been using his account an the presence status change from available to away or offline.

• On a computer, a user's presence becomes Away automatically if they're inactive for a few minutes or if the computer is locked; and it becomes Offline when the computer enters sleep mode.
• On a mobile device, a user's presence becomes Away whenever the Teams app is in the background, and then becomes Offline after 24 hours of inactivity.

If a user is logged in to Teams on two or more devices (e.g. on both a desktop computer and on a phone), then the device where they were active most recently determines their presence. For example, if a user is logged in on both a computer and a mobile device, and they're currently working on the computer, their presence will come from the computer. When they disconnect on the computer, their presence will then come from the status of the mobile device.

You can use the following link for reference:

User presence in Teams - Microsoft Teams | Microsoft Learn

According to your situation as teams is running in the background , the teams presence status will become away, after teams status changed to away you should be able to see the last see status.

You can check the above information and let me know how it goes, if you need any further assistance please free free to reply here, we will work together to address the concern. Thank you for your time and understanding. I really appreciate your cooperation.