Using Classic Outlook on Windows for personal email, calendar, and contact management
This problem affects the outlook.com contacts as well. On my Android phone, all pictures for contacts disappeared, but everything else seemed normal which was strange. I logged into outlook.com and the contact list there and details for contacts is at least 6 months old.
I was able to export my contacts on my phone to a VCF to preserve them, but I'm not sure how much was actually changed or lost.
I hope the contact list gets restored. I can't imagine what this will be like if millions of people's data is lost or is out of date.