How I interpretate this plot from matlab

This algorithm

https://www.dropbox.com/sh/zn9b5xgssmkhnqa/AACJucOyiLcs-1WOmwerQyf3a/Subroutines?dl=0&preview=get_parent_child_map.m&subfolder_nav_tracking=1

tries to connect cluster of cells from single cell sequencing data in 2 adjacent time points to each other in a parent-child way (later and earlier time points). Here as a control to see if I am running the code right, I put 3 clusters of cells from one time point and tried to connect clusters to each other; For example if I have clusters a, b and c, I expect a be more similar to a, b to b and c to c (as I am comparing one time point to itself); But what I am obtaining is not interpretable as this picture.

As you are seeing, in first column cluster a is the most dissimilar to cluster c but in third column c is not the most dissimilar to a anymore. Here, likely the number of similar cells in each clusters have been decided to sum of the column based on this lines of code from the source

if column_normalize==1 % Column normalize

    for i = 1:size(raw_vote,2)

        a = raw_vote(:,i);

        b = a/sum(a);

        [sorted_b,sortingIndices] = sort(b,'descend');

        assignment_probabilities = [assignment_probabilities b]; 

        parent_assignments(i) = sortingIndices(1); % parent for child cluster i

    end

Whatever I am reading this code I don't know how to interpret this picture. I ask the developer, he sent me his sample inputs files https://www.dropbox.com/sh/8856ij1nlk6ehiq/AADS0CjwfTxmlBpmGMDSxtWRa?dl=0 but did not help me to get the point.

Could somebody help me in interprating this plot?

Thanks a lot in advance