It's not surprising with many working and studying remotely as a result of the COVID-19 coronavirus pandemic that demand for cloud services is up. Microsoft has been monitoring that situation in regard to Office 365 and has started taking action to preserve overall performance by throttling some services.
On March 16, Microsoft posted to Microsoft 365/Office 365 admin dashboardds a warning about "temporary feature adjustments" that it might take. That warning told customers that Microsoft was "making temporary adjustments to select non-essential capabilities." Officials said they did not expect these changes to have significan impact on users' experiences. Among the examples of the types of changes Microsoft might take would be things like how often its services check for presence; intervals in which other parties typing are displayed; and video resolution.
Today, March 24, Microsoft started cautioning Microsoft 365/Office 365 commercial users of some other "temporary changes" they should expect. The list:
OneNote in Teams will be read-only for commercial tenants, excluding EDU. Users can go to OneNote for the web for editing.
Download size and sync frequency of file attachments has been changed.
We are rescheduling specific backend operations to regional evening and weekend business hours. Impacted capabilities include migration, DLP and delays in file management after uploading a new file, video or image.
Reduced video resolution for playback videos
People timeline has been disabled for newly uploaded videos. Pre-existing videos will not be impacted.