Possible bug with argument parsing in git blame

debayan@deep-blur:~/testrepo$ git blame 22621a32..8486802f -- dir/subdir/newsubdir/b

81531975 b (debayan 2010-05-13 15:32:17 +0530 1) four 81531975 b (debayan 2010-05-13 15:32:17 +0530 2) five d700ac9c b (debayan 2010-05-13 15:33:27 +0530 3) blah 2656ab56 b (debayan 2010-05-13 15:33:34 +0530 4) bleh d0c6e851 b (debayan 2010-05-13 15:42:21 +0530 5) foo 7bf5510e b (debayan 2010-05-13 15:42:53 +0530 6) yo c4515289 b (debayan 2010-05-13 15:43:10 +0530 7) lala a257c7e4 b (debayan 2010-05-13 16:03:46 +0530 8) yes ed8e4601 b (debayan 2010-05-13 16:03:55 +0530 9) np e96d14bf dir/subdir/newsubdir/b (debayan 2010-05-13 16:05:05 +0530 10) yo dace00d1 dir/subdir/newsubdir/b (debayan 2010-05-13 16:05:11 +0530 11) boye 8486802f dir/subdir/newsubdir/b (debayan 2010-05-13 16:07:51 +0530 12) what?

debayan@deep-blur:~/testrepo$ git blame 22621a32..8486802f dir/subdir/newsubdir/b fatal: cannot stat path 22621a32..8486802f: No such file or directory

The only difference between the first and the second command is the "--" separator. Is this normal behaviour?