Not sure, but a BFF's mom's phone was doing something similar. She had T-Mobile. Whenever she called her daughter, it didn't pop up as a name or number, but an address. This wasn't her home address, nor was it her work address, nor was it even remotely close to either of those. It was always the same address whenever she called, though.
The only reason people get lost in thought is because it's unfamiliar territory.