The probability is high and I will explain how it can happen. The first vote can come from a particular member of a local board who have earned the respect and trust of other local board members, others coming to vote, sees his/her choice and decide to vote in same direction. It happens even  in circular politics  in which case people simply vote for a candidate because a certain individual supports the candidate. I don't think this breaks any rule hence, taking any action because some people voted the same numbers and in the same order may not seem fair to the competition entirely. Like some people already suggested, these are areas of improvement that can be discussed after a winner have been announced based on the rules set for this year's contest.

By the way, your observation is right as I have noticed that pattern across many local boards and it simply means there could be coordinated effort to deliver pizza from some local boards.