Hi Greg,
What you’re seeing in Outlook.com is the “Conversations” view. This view groups emails by subject line into expandable threads, which is why each group has a drop-down arrow. It can appear unexpectedly if the conversation view setting was accidentally turned on or updated in Outlook.
To turn off the Conversations view and see emails individually:
Open Outlook.com and go to your Junk Email folder.
At the top-right of the email list, click the Filter dropdown.
Select Filter → Show as → Messages.
Messages will list all emails individually.
Conversations groups emails by subject (the current view).
After this change, emails will no longer be grouped under drop-down menus.