Hi Markus
I'm AnnaThomas and I'd happily help you with your question. In this Forum, we are Microsoft consumers just like yourself.
This must be due to the new Teams as you pointed out. You can try updating Teams to the latest version and if that doesn't work, you can give feedback to the Teams developer about the issue
https://support.microsoft.com/office/a557a90a-828c-482f-8a71-f933499e70f4
Best Regards,
AnnaThomas
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