Strange annotated tag issue

[Robert Dailey <rcdailey.lists@gmail.com>]

I have a particular tag in my repo that shows 2 annotated
descriptions, which is very confusing.

The command I ran:

```
git show --format=fuller 4.2.0.1900
```

And the output:

```
tag 4.2.0/1900
Tagger:     John Doe <john.doe@domain.com>
TaggerDate: Fri Jul 18 10:46:30 2014 -0500

QA/Internal Release for 4.2.0.19

tag 4.2.0/1900
Tagger:     John Doe <john.doe@domain.com>
TaggerDate: Fri Jul 18 10:46:15 2014 -0500

QA/Internal Release

commit 2fcfd00ef84572fb88852be55315914f37e91e11 (tag: 4.2.0.1900)
Author:     John Doe <john.doe@domain.com>
AuthorDate: Thu Jul 17 11:20:17 2014 -0500
Commit:     John Doe <john.doe@domain.com>
CommitDate: Thu Jul 17 11:20:17 2014 -0500

    Commit description
```

Why does it show two entries? In my `packed-refs` file, it also shows
a strange revision for the tag (I expect to see just 1 SHA1). Not sure
if it is related:

```
66c41d67da887025c4e22e9891f5cd261f82eb31 refs/tags/4.2.0.1900
^2fcfd00ef84572fb88852be55315914f37e91e11
```

Note I'm checking all of this on a bare clone (used `git clone
--mirror`). Can someone help me understand what is going on here? I
found this issue because I'm trying to do `git lfs migrate import`,
and it isn't processing my tag because of this.