Microsoft is changing how the “Allow Guest Access in Teams” setting works (from the Microsoft 365 admin center). Because few tenants switch this setting on and off, the change might not be noticeable. However, it’s a good one because it might help change the way Teams deals with disabled accounts. And if you want to control guest access, you should really use an Azure AD B2B Collaboration policy instead of the on-off switch.
https://office365itpros.com/2021/06/28/why-microsoft-is-changing-how-the-teams-guest-access-setting-...
