Possible bug in `git reset` in 1.9

Suppose I have the following branches:
* branch-1 with commits A - B - C
* branch-2 with commits A - B - C - D

Prior to version 1.9, running `git reset --hard D` while branch-1 is checked out will result in changing the current branch HEAD to commit hash D (essentially what update-ref would do).

In 1.9.1 (I haven't tested on 1.9.0 yet), however, running `git reset --hard D` while branch-1 is checked out will result in the following output: $ fatal: Could not parse object 'D'

I assume that this is not an expected change as nothing about changes to the reset command is present in the change log for 1.9.0 or 1.9.0. Is this a bug or was the previous behavior unexpected as well? Either way, it's a regression in terms of what can be expected based on previous version.