As of Feb. 17, the scheduled maintenance is finished. Other details in the following are unchanged.

(2021/2/15)
The entitled event informed is known to happen, to target users who self-signed up before Mar. 2017, and recorded meeting within (EES) Microsoft Teams during　Jan. 26~Feb. 18(Wed.).

The system is arranged to fix the failure on Feb. 17(Tue.), am9:00~am12:00.
Amid the operation, MS office 365 and MS Teams serve as usual.

For the above mentioned target users, you can find where the recording data is store, refering to How to find where your MS Teams meeting recording data is stored?.
the data stored in OneDrive for Business or Share Point may be accessed by other users.

(2021/1/29)
When recording meeting within Microsoft Teams, the video may be stored to OneDrive for Bussiness,instead of Stream as usual. The reason is under investigating but you can restrict the access of your video by the following way:

1.  Right-click the video uploaded to Teams
2.  Select “open Share Point”
3. Download the video on Share Point to your local PC
4. Delete the video on Share Point (so it will not be accessed by other users)
5. Upload the video to Stream, and assign the access permission to the users/groups you like.