My own thoughts --> I think a couple poll voters simply wanted to be in the leading edge by putting BU in their polls.
Note a few guys also have Purdue, Nebraska, Oral Roberts, BYU on their ballots, while Creighton was almost everyone's choice even to be in the top 15, and now with one loss they drop totally off the planet and get nary a vote.
These poll votes are not being that realistic, maybe more wishful.