The m output matrix contains only 2 columns. I suppose you are referring to the first output argument, c. The matrix c should always contain 6 columns. From the doc:
Matrix of multiple comparison results, returned as an p-by-6 matrix of scalar values, where p is the number of pairs of groups. Each row of the matrix contains the result of one paired comparison test. Columns 1 and 2 contain the indices of the two samples being compared. Column 3 contains the lower confidence interval, column 4 contains the estimate, and column 5 contains the upper confidence interval. Column 6 contains the p-value for the hypothesis test that the corresponding mean difference is not equal to 0.
If the first output has only 5 columns, can you include reproduction code so that we can see what's going wrong? Don't forget to attach your data as a MAT file so that we can run your code.
Thanks.
