I think CO was making a large database change this weekend. I happened to check on a BF reward flight to LGW between Christmas and New Year’s, and my final segment from IAH to AUS had changed. The reservation also showed that my BF flights from IAH to LGW and back were now showing coach. When I called the Elite Desk to clear up the matter (the CSR saw that the reservation was really BF) she couldn’t rebook my seats because all the flights were locked. This morning, however, all the seats were back, so I guess the database update has finished.