Microsoft Teams cannot create meeting notes for a meeting in the General Channel

Deleted  Would you be able to share a screenshot with the channel options?

I have a very similar issue:

1. when I create a new meeting without a channel selected, the "Add agenda others can edit" section is available in the meeting details and I can later add notes during the meeting

2. as soon as I select any channel (or if I start creating the meeting in a channel instead of the calendar) that section disappears and notes are not available during the meeting.

You also mentioned "Only users with proper permissions can access this feature"- what exactly is this permission?