They were probably physically where they were recorded both
times. The dates are far enough apart that they may have moved. I'm
surprised at a December date for a census report. I wonder why it
was done so late. Or was this a state or local census? You about
have to use both as sources and try to explain the differences in other ways.
I have a similar thing for 1880, though the records make it clear
which was the place I should record as being their home.
On June 5, 1880 my great-grandfather as a 3-year old child is
recorded with his parents and no siblings in Clark County Ohio in his
father's household - and his mother's parents were recorded next door.
On June 10/11 1880 he and his parents and a 1-year old sibling were
recorded in Sedgwick County Kansas in the household of his father's
parents (who had moved there earlier that year).
Assumption: Their residence was Ohio. They visited grandparents in
Kansas less than a week later.
Question: the sibling (born in 1878) missing in the Ohio record was
not next door at his grandparents' house (according to their census
record) and was listed as a year old less than a week later in
Kansas. He was actually born in 1878. Where was he? Was the census
taker sloppy?
Question: In 1880 how long would it take to get from Springfield,
Ohio (just west of Columbus) to a town near Wichita, Kansas? It was
probably near a direct railroad route. One day - maybe 2?
Margaret