MS Teams New Meeting Experience auto-unchecked

PDostiyar This behavior actually appears to be working as Microsoft intended.  In this article, it states:

What happens to the new meeting experience if I sign out of Teams or switch to a different Teams org?
If you sign out or switch to a different Teams org (also known as a "tenant"), you'll have to turn on the new meeting experience again. Follow the instructions for turning it on in Settings and restarting Teams.

https://techcommunity.microsoft.com/t5/microsoft-teams-blog/new-meeting-and-calling-experience-in-microsoft-teams/ba-p/1537581

Microsoft is supposed to be changing that option to be defaulted to On and you have to opt out in the near future which will then keep the box checked even after a sign out.