I already knew about this. Can you provide any information about the name's background?
The name come from an old West Slavic Tribes called "Kujawianie" in Polish. I guess it would just be "Kuyavians" in Anglicized form. They were located and set up town, grody, in what is now Kujawy. My guess is that that got absorbed with the Christianization of Poland. Though, as the region's name indicates, their identity didn't vanish completely.
Maybe they indeed have some connection to Ukrainian Kuyavia. Would be a topic worth doing some research on.