Were points actually deducted for the reservation? Call CS to confirm, but yes, both systems historically had problems displaying points/dealing with reservations when categories changed. They don't store the points requirement with the reservation, just the property name. And when you bring it up on-lin, it looks up the category/points via the name, so only have current information.
Poor system design, but it is what it is.
There have been reports of more significant issues if you didn't actually pay with points before the price went up.