I have had this problem, too. It isn't necessarily the result of sloppy research. It might be because someone added the person via the Ancestry iPhone app. When using the app, one can type in the first few letters of a location and, voila!, a number of different locations occur from which to choose. Because many places in the U.S. are named after places in Great Britain and Europe, there might be a city or village in England that has the same name as a city in the US. On the app, both would show up, and the person using the app would have to choose. The iPhone screen is so small that it is easy to attempt to touch a city in Europe, but to accidentally touch the American city instead, without ever realizing it. I have done this several times myself, and have noticed it on other's trees as well.