This seems to just be some unweighted survey, not sure why 538 added this. The party registration of the sample is very out of line of the actual statewide party registration composition (way too Dem) and it's also way too old.
Kentucky actually has one of the highest percentages of registered Democratic voters in the country. LOTS of DINOs and ancestral Dems. I’m not sure of the exact numbers nowadays, but they did specifically ask about what party you are REGISTERED as, not identify as, so it might not be as big a deal as you think.
