Welcome to the wonderful world of Central and Eastern European national boundaries. Every one of those nationalities you mention is probably the truth, for the year in which it was stated. Those of us with family from those regions will see it over and over again.
My grandfather was born in Warsaw, which you and I might unambiguously say is in Poland, right? He was born around the turn of the century and came to the US as a teen. He grew up speaking both Polish and Russian. One day I referred to him as being Polish. He said "Polish, Russian...depends on the year." In other words, even people living in those places during those times were quite aware of the changes.
Another example? My mom's family is 100% Hungarian. Except that both her parents are actually Slovakian. When they weren't Austrian or Austro-Hungarian or Czechoslovakian. They mostly spoke German. One of my Hungarian great uncles was born in what is now Romania. Other Hungarians were born in what is now the Ukraine.