I've run into this phenomenon a few times myself. More often I find a single individual counted twice--e.g. once with his own family, and once with the family to which he was hired out as a laborer.
Were both families enumerated by the same censustaker? It would seem unlikely that someone would forget interviewing and enumerating a family, and repeat the process a day or so later. Perhaps there were two censustakers in the area, and one strayed into a ward where he didn't belong. The family might have been so nervous about having a "government official" in their home that they failed to mention the previous visit. Or perhaps they just chalked it up to bureaucracy.
Since the two enumerations don't quite match and are only two pages apart, perhaps the censustaker was the same, but the informant was different in each case. A husband and wife might give different accounts of their family (I would guess the wife's would be more accurate).
It would be interesting to collect instances of double-enumerations, and figure out how they occurred, compare for accuracy, look for regional trends, urban vs. rural, etc.