Not sure if it's what they meant, but the boundaries move, so the timezone you store in a location today may not be the one that it corresponds with in a year.

Not sure if it's what they meant, but the boundaries move, so the timezone you store in a location today may not be the one that it corresponds with in a year. https://en.wikipedia.org/wiki/Time_in_Indiana https://en.wikipedia.org/wiki/Time_in_Indiana