I am currently running MS Teams in Linux distributions (arch-Linux, ubuntu). The application is working great except for the autologin. Every time I turned on my laptop, I need to type my credentials to sign in. I have tried both versions "insiders" and "preview" on ubuntu and arch and I faced the same issue.
On the other hand, I installed MS Teams on a Windows-based machine, and the autologin works great which means is not related to my account security settings.