git log --no-walk --tags produces strange result for certain user

From: Kirill Likhodedov <kirill.likhodedov@jetbrains.com>
Date: Dec 3, 2013, 10:08 UTC
Message-ID: <5EE449B7-AB75-4EFF-85F9-292727FA1C53@jetbrains.com>

Hey,

I use the following commands to receive the list of tags together with hashes the point to:
  
    git log --tags --no-walk --format=%H%d%x01 --decorate=full

Generally it works fine, however a user reported that for his repository this command returns the list containing several hashes without tag references. Something like this:

    05c9a3a6247698ff740ca3a79828456347afdcef (HEAD, tag: refs/tags/2.33, refs/remotes/origin/master, refs/remotes/origin/HEAD, refs/heads/master)
    a7fda708d76d7f83d5a160b6b137b98b7677f771 (tag: refs/tags/2.44)
    f119c2e7c69bb5ed1da5bae29c8754550ab96bde
    07385a6ebe5a2e01e6ba9c8d0cb7b15c9a13f65d (tag: refs/tags/1.69)

Here third hash doesn't have a reference. There are 3 such hashes in his repository.

How can this happen? Is it a bug or some special scenario?

* I've already asked the user to execute `git tag --points-at` on these "suspiciously tagged" hashes: nothing was returned.
* `git show --decorate=full` executed on these hashes return commit details, and no references on them.
* From the log user sees that these hashes indicate some "normal" commits, nothing special at first glance.

Git version that he uses is 1.8.4.0.

Thanks!

-- Kirill.