Microsoft Advisories about Some Users Receiving Duplicated Emails on 7 May

The following provides the summary of Microsoft Advisories issued on 7 May 2020 (Thur) which caused some users receiving duplicated emails on that day.

Users Affected	Some staff & students
Start Time	7 May 2020 (Thur) 11:30AM
End Time	7 May 2020 (Thur) 3:15PM
Cause	Microsoft issued the root case as “there was a configuration issue with a recently established block, that was designed to move a users unread spam emails into the Junk mailbox”.
Service Affected	Some users were receiving duplicate emails as unread which have already been read. This issue affected some users and might have affected any email that was read recently.
Status	Microsoft reported that they reconfigured the block successfully and resubmitted the affected emails, which mitigated impact. They would review the block configuration procedures to prevent the problem from happening again.