Counted twice in 1870

So I'm going through records on the Family Search Pilot website looking for documents to confirm data that I had already known from elsewhere (but didn't make note of the references when I added the information last time).  I'm finding some new information, like a few new siblings to family members that I already knew.  But in the 1870 U.S. census, I found records that show what looks like a double counting for at least one family.