She may have decided that she prefers canned food. Or she is sick of that particular brand of dry food (Jamie stops eating a brand after about three months, and won't eat the same brand more than twice a week, so I'm constantly rotating). Also, even though it's a new bag, there may be something wrong with it (does it smell rancid?), or the ingredients may have been changed.
As Pat said, what's important is that she's eating, so I wouldn't worry too much about the dry at the moment.