When performing a cutover on a Teams Group the Channel Messages (Chat History) are not migrated and the following error is displayed in the log:
Problem copying team channel messages 'Important', or no permission. Team=Owner=Testteam3@contoso.onmicrosoft.com.Status Code: Forbidden
If this does not resolve the issue, increase the allowed OneDrive errors in the migration profile used for migrating Teams.
Contact Product Support if you have any issues with the above resolution.