They said it was because I "made a change". I was not able to get more useful information because of the language barrier (the hotel is in japan).

Edit: After thinking about it some.... I had back to back reservations. I think they did not see the other reservation and are wanting to take points out of my accounts for those nights as they incorrectly believe I extended my reservation at checkin.

The platinum desk said that I shouldn't worry about it. I hope they are correct.