Meeting notes tab missing?

I had exactly the same issue as described. When I go via Calender to a meeting where I am an organizer I have no option for the meeting notes. Since I was able to create meeting notes in some occasions I search using search bar and the I found a work around.
From left side bar with options like (Get Start, Activity, Chat, Teams, Calender, Calls ....)

select "Chat" then

Search for the meeting in Chat Recent (it is order by time and has calender symbol)

Click on the meeting and I had success, now I was able to create the meeting notes since the tab for meeting notes is now available.

I was in the same organization as the organizer and or I was the organizer. The meeting had less than 20 participants.

I hope it works for you also.

After this works you can go Calender, Select the meeting, if meeting is open, select chat and then you will see the meeting notes