Yep. I sign in once when the app is opened (which happens automatically as I’m logged into the computer as my Entra ID) and then am never prompted again until I close and reopen Teams.

Something is misconfigured in the environment, or there is a security policy that is set way too high, or one is scoped incorrectly. It is definitely not the normal or expected user experience.

Teams has a lot of faults, but that one is on your org’s admins and security team. Hopefully for you it’s a mistake and not done intentionally.