Hi, Lynn
Good day!
Thank you for posting to Microsoft Community. We are happy to assist you.
According to your description, the issue of your concern that your meeting notes tab was missing on your Teams.
Based on our searching and tests, here's the feedback from many users and experience as below:
- This is expected behaviour that the MeetingNotes tab is missing in the calendar details page because of the HybridCalendar rollout. There is also a known issue on the Calendar details page that clicking on the Notes icon, will not do anything.
- The feature has been rolled out to 50% in General Ring. Some users will still see the old behavior.
- Workaround- If users are not seeing the meeting notes in calendar, alternate way is to go the meeting chat and access the notes.
At this moment, we highly recommend you use the workaround, and this would be let you able to use this feature. Hopefully.
If the issue persists, we would like to refer you to contact Microsoft Online technical support team which they can help you through the remote.

Ref: Get support for Microsoft 365 for business-Online support.
We believe they would conduct in-depth of this issue and provide you a more professional suggestion.
Thanks for your precious time and your understanding would be highly appreciated.
Have a nice day,
Alex | Microsoft Community Moderator.