In this example from District 16, Waco, McLennan County, Texas, in the 1930 census, the birthplaces of the parents are switched.
Since the people in this listing (L. Lloyd Edmonds and his 4 children) are lodgers, their relationship to each other is not indicated in the census. However, I know that Amanda M., Lloyd Jr, Lee O., and Vivian are the children of the widower. (I also know that they spelled Loyd with one L rather than two.)
You will note that the father’s place of birth is listed as Texas, but the place of birth of father on each of the children’s lines is listed as Tennessee. If you took this at face value, you would think that Loyd might be an uncle rather than the father of these 4 children. However, the birthplace of the mother is listed as Texas. In reality, the two columns (birthplace of father and birthplace of mother) are swapped. Their deceased mother was born in Tennessee.
This makes one wonder if the entire page is similarly transposed, or possibly every page completed by this particular enumerator.
This is just one more thing that we have to be on the lookout for.