Because people don't look on the Help forums: https://www.bungie.net/en/Forums/Post/219463451?sort=0&page=0
And if you are that lazy to click and look:
[quote]Updated 12/23: Emerging Issues
The following items are player reported issues which we are currently investigating:
Three of Coins from Xûr
Xûr will not be selling Three of Coins for the weekend of 12/23 - 12/25. [u][b]We are investigating his expected behavior for the weekends to come.[/b][/u][/quote]
Key word is investigating, not fixing or working on it, but investigating. Besides, the staff doesn't work in the second half of December. They will not return until next week, so I didn't even expect a fix of any kind.