Some emails get skipped during email archive process
When an Outlook email is archived by multiple users, if the message date and time are exactly the same, the email message only gets archived once. The “owner” is the last person who archives the message except as noted below.
If you ran the archive with Skip previously archived Email turned On, the process ignored the email message and does not change you to the owner. If you run the archive again with the Skip previously archived Email turned Off, it should make you the owner and add a checkmark next to the message in Outlook.