Two 1996 Christmas Postmarks

Two different Vatican Christmas Day (12/25/1996) postmarks. Same 1995 Christmas stamp, Towards Holy Year 2000 - The Nativity. (Scott 997) Addressed to same location, with different names. Any thought on why the 1995 Christmas stamps were used for 1996 Christmas postmarks? Here is a third cover, Same date 12/25/1996. Any more? Check your collections and let us know ...