having to pull twice

I'm finding this happening from time to time.

soulierm@espresso:~/work/mitel-msl-tug$ git pull
remote: Counting objects: 97, done.
remote: Compressing objects: 100% (54/54), done.
remote: Total 65 (delta 34), reused 0 (delta 0)
Unpacking objects: 100% (65/65), done.
From pa:git/mitel-msl-tug
   92437d6..9c784c8  master     -> origin/master
Updating 92437d6..9c784c8
error: Entry 'mitel-msl-tug.spec' not uptodate. Cannot merge.
soulierm@espresso:~/work/mitel-msl-tug$ git status
# On branch master
# Your branch is behind 'origin/master' by 4 commits, and can be fast-forwarded.
#
nothing to commit (working directory clean)
soulierm@espresso:~/work/mitel-msl-tug$ git pull
Updating 92437d6..9c784c8
Fast forward
 mitel-msl-tug.spec                                 |    7 +-
 .../etc/e-smith/pgsql/init/tugdb.sh/20auth         |    4 +-
 .../etc/e-smith/pgsql/init/tugdb.sh/50apps         |   37 ---
 .../etc/e-smith/pgsql/init/tugdb.sh/90loaddata     |    8 +-
 .../etc/e-smith/pgsql/init/tugdb.sh/95schema       |    2 +-
 root/etc/e-smith/templates/etc/tug/tug.ini/00setup |    2 +
 .../e-smith/templates/etc/tug/tug.ini/10teleworker |   37 +++-
 .../templates/etc/tug/tug.ini/11teleworker_fixed   |    1 -
 .../e-smith/web/django/teleworker/scrc/views.py    |   11 +-
 root/usr/lib/scrc/migrate.pl                       |  322 --------------------
 root/usr/lib/tug/migrate/30_add_scrc               |    2 +-
 root/usr/lib/tug/migrate/31_add_scrc_connections   |   22 ++-
 12 files changed, 77 insertions(+), 378 deletions(-)
 delete mode 100755 root/usr/lib/scrc/migrate.pl
soulierm@espresso:~/work/mitel-msl-tug$ git --version
git version 1.6.0

When I pulled the first time, I was told that one of the files was
 not up-to-date, but status did not note any modified files. The
second pull then worked as expected.

That directory is mounted via NFS, and I'm curious as to whether some kind of time skew could be the problem. But then, if it is, why did it go away after the first pull?

Thanks, Mike