Is there even any population in the Kentucky bend? If not, then I don't see a contiguity problem.
More generally, I don't see contiguity as a problem as long as political subdivisions (i.e., states, counties, cities, places, etc.) are being kept whole. A whole subdivision cannot, by definition, be non-contiguous in a way that is relevant for political redistricting.
Yes, at the end of the day, the state lines win. Maine was once a part of Massachusetts while NH and VT were already separate states. MA also had a
lot of CDs at that time. Do we have a map available to see if any of them mixed part of modern Massachusetts with modern Maine?
In the modern day, there have occasionally been proposals to make Puerto Rico part of Florida or New York.
