Keyword Search returning unexpected results: 9 instead of 1

When we do a keyword search for “Who’s”, 9 results are returned, but they are all the same document.  When you do a keyword search for “whos” (without apostrophe), 1 result is returned.

Only 1 result should be returned, it is this one: http://workday.yale.edu/training-materials/yale-population-types-whos-wo…

Is this a bug, or did the person entering the information do something incorrectly in the keyword search field?

Thanks!

Beth