Additional meeting and call-related features and issues within Microsoft Teams for business
If you are creating meetings in Outlook, that may be the issue. I posted the problem last year. Since then, I have discovered that if I create the meeting through the Teams app (using the relevant account) rather than Outlook and if I join the meeting through the Teams calendar, I have no problems. The Teams calendar still syncs with Outlook so I can manage a single calendar. I just have to use the Teams tool for creating and attending Teams meetings.