Cackle has always been honest about their birds, at least they have been for the past several years. In this situation, I think it's the feed store that was pushing them as Ameraucana, or they were working off of some very old/outdated info.
Up until about 1978, Easter Eggers were called Ameraucana. But then the Ameraucana got official recognition as a breed. Hatcheries just never changed their breeding practices or marketing to conform to the new breed standard. They just kept doing what they had always done, and most still do.