Additional meeting and call-related features and issues within Microsoft Teams for business
Thanks for the tip for the workaround for the flickering problem by first opening Teams and THEN click the Outlook reminder "Join" meeting button .
Hopefully this bug is fixed soon by the engineers.
I am glad it helped you.
A Microsoft representative has advised that there is a bug open for this and it will be resolved in the October 2023 update that is coming out.