Birthdays synced with Outlook.com display on the wrong date

[RobMahn]

Please see the Thunderbird Calendar bug report:
https://bugzilla.mozilla.org/show_bug.cgi?id=1860303

Since this problem is related to TBSync, I thought it important to document here also.

While this is likely a problem with Thunderbird Calendar taking an incorrect default SEQUENCE, this probably would not have shown up if TBSync filled that value.

[RobMahn]

Further testing:

1. Create an Outlook.com test person with a birthday.
2. Sync to Thunderbird.
3. The new birthday will not display correctly.
4. Export the birthday calendar to .ics and edit to save only the test birthday.
5. Restart Thunderbird. The birthday now displays correctly.
6. Delete the test person from Outlook.com
7. Sync to Thunderbird to remove the test birthday.
8. Import the .ics file with the test birthday.
9. The birthday displays correctly.

My conclusion is that TBSync is not refreshing the calendar after a sync.

You can only see this problem when a new birthday is synced and you have not yet restarted Thunderbird.