Strange happening with 'git fetch'

This is very strange, and defies the understanding of everyone in the office familiar with git.  Is it a bug, or some feature we don't understand?

Basically, when I do a 'git fetch', it updates my local repository. Now nobody else is doing anything, so the remote repository does not change.  Doing another 'git fetch' should report that nothing needs to be done and nothing should change.  But instead, it reports something about the remote HEAD, and changes my local branch 'master' to some strange location!  Running 'git fetch' again restores it to the correct state, reporting that it is updating 'master'.  Repeated invocations will toggle between these two results.  Below is a transcript from the bash shell.

Can someone please explain this?

---- bash console ----
dkirk@RI-ENG-21 /c/Dev/TSWeb2 (master)
$ git fetch
From //10.18.0.53/git/repos/WebTrading
 + 03c60a4...209b0bc HEAD       -> origin/HEAD  (forced update)

dkirk@RI-ENG-21 /c/Dev/TSWeb2 (master)
$ git fetch
From //10.18.0.53/git/repos/WebTrading
 + 209b0bc...03c60a4 master     -> origin/master  (forced update)

dkirk@RI-ENG-21 /c/Dev/TSWeb2 (master)
$ git fetch
From //10.18.0.53/git/repos/WebTrading
 + 03c60a4...209b0bc HEAD       -> origin/HEAD  (forced update)

dkirk@RI-ENG-21 /c/Dev/TSWeb2 (master)
$ git fetch
From //10.18.0.53/git/repos/WebTrading
 + 209b0bc...03c60a4 master     -> origin/master  (forced update)

Thanks, -David