Scheduling and managing events using Outlook.com calendar
Before we ask for your email address, please tell us the things you've done so far in your attempt to fix this on your own.
I was discovering that birthdays of well maintained contacts are missing in birthday calendar and wondering about that - for weeks. Manual refresh in birthday calendar settings doesn't help.
Thanks to lamé's investigation the issue should be clearly reproducible. Meanwhile, in the German forums it's confirmed that not only linked contacts (Skype, Facebook) but also pure standalone Outlook contacts are affected and not properly synced.
Thanks.