Census answers can appear to be wrong for a variety of reasons. Most of those stem from issues with the informant or the enumerator. Sometimes the “wrong” information is not really wrong at all and is the result of the genealogist not being fully aware of the instructions given to the census enumerator.
Of course some enumerators did not follow instructions. Others did. In preparing for my webinar on the upcoming release of the 1950 US Census, I discovered this reference to how places of birth are to be handled in that enumeration. Quoting from the instruction manual’s instructions on item 13 (place of birth):
For a person who was born in a hospital or elsewhere outside of the State in which his family was living at the time he was born, enter the State in which his family was living—not the State in which the hospital was located.
While I’m not seen the 1950 census enumeration for my parents yet, this means it could unexpectedly indicate they were born in Illinois. They were not. They were born in Iowa–in a hospital just like referenced in the instructions. Their parents were Illinois residents, but the nearest hospital was across the Mississippi River in Keokuk, Iowa.
Without knowing the instructions, I might have though the answer was wrong. If it says “Illinois” the enumerator was just following orders.
And of course, when I transcribe that entry (when I find it after the 1950 census is released on 1 April 2022), I will transcribe it as it is on the entry. I will not change it. I will not fix it. I will make a notation about the location and the enumerator instructions.