System Glitch
I talked to an INS officer about 7 months ago and he pointed out that most of this online status changes are done manually, so there are a lot of changes. I did in fact change my address before I got the message that my interview was cancelled, but it was a "in-town" move so I did not switch DO. After some time I did received an interview letter and had my interview a week ago. So don't pay attention to what the status say. I might change in the future.
Hope this helps,
Flyer