Birthday Calendar no longer updates from Contacts

A few days ago I noticed that WLM had some (not all) of my contact's birthdays one day off.  I fixed about a half-dozen of them and now these events have disappeared from my Birthday Calendar.  No amount of refreshing or signing off/on has succeeded in bringing them back.  Birthdays I did not edit are still in the calendar.  The new birthday information is correct when I view the Contact via WLM or Outlook.com but the associated birthday events have disappeared from the Birthday Calendar in both platforms.  How can I get these to reappear?  I'm screwed if I forget my wife's birthday.