Is the comm command broken on Mac?

Question

Suppose there are file1:

1
2
3
5

And file2:

2
3
4

When comparing them with comm file1 file2 on FreeBSD or Linux, I got the following result:

1
                2
                3
        4
5

But when I tried the same command on Mac OSX 10.9, the result surprised me:

1
        2
        3
    4

Is the comm command broken on Mac? Or am I missing something?

Answer 1

Works correctly on my Mavericks based iMac:

iMac:~/tmp: cat file1
1
2
3
5
iMac:~/tmp: cat file2
2
3
4
iMac:~/tmp: comm file[12]
1
    2
    3
    4
5