git update --prune issue

I have an unreliable problem when using "git remote update --prune". git claims that many refs from a particular remote do not point to a valid object, but only after finishing another update.  I've included a shortened version of the output from one particular instance of the issue.  Note that the errors are printed for every subsequent remote as well.  However, after the update is completed, everything is fine.

It seems to only happen when there are non-fast-forward changes (new branch, forced update, pruned branch).  The issue only happens with this particular remote, which I've tried removing and recreating, and is the same type of remote as all my others (another user's NFS-mounted home directory).  However, my remotes are all individual developers, and this developer is the only one who ever rebases her working branches.  (recloning the repo from origin and setting up my config and remotes all over again has also had no effect)

Unfortunately, I have been unable to reproduce the problem in any test repos - for example, though a forced update and a pruned branch in the problematic remote along with an update in another remote seems to fairly reliably produce the problem in this repo, recreating that situation in another repo doesn't cause any problems.  Sorry for the incomplete bug report, but perhaps this will be enough to go on!

Thanks, Jeffrey

I've seen the issue in previous versions built from git.git master, as well as v1.6.3.3, but for this particular one:

$ git --version git version 1.6.5.1.61.ge79999

$ git remote update --prune
Updating origin
remote: Counting objects: 42, done.
remote: Compressing objects: 100% (9/9), done.
remote: Total 15 (delta 9), reused 12 (delta 6)
Unpacking objects: 100% (15/15), done.
From /users/cxtfcm/CxTF_DB
   88b8613..d40f26d  2009.Q4    -> origin/2009.Q4
   d40f26d..56305b8  dev        -> origin/dev
Updating steph
remote: Counting objects: 299, done.
remote: Compressing objects: 100% (241/241), done.
remote: Total 276 (delta 186), reused 19 (delta 6)
Receiving objects: 100% (276/276), 41.09 KiB | 10 KiB/s, done.
Resolving deltas: 100% (186/186), completed with 17 local objects.
From /users/sdewet/CxTF_DEV/CxTF_DB
 + c2439dd...69cb5c3 beta_gc_dev -> steph/beta_gc_dev  (forced update)
 + fb25173...f0e4963 beta_veh_dev -> steph/beta_veh_dev  (forced update)
 * [new branch]      beta_veh_dev_old -> steph/beta_veh_dev_old
Pruning steph
URL: /users/sdewet/CxTF_DEV/CxTF_DB/
 * [pruned] steph/beta_gc_dev_old
Updating kevin
error: refs/remotes/steph/beta_gc_dev does not point to a valid object!
error: refs/remotes/steph/beta_veh_dev does not point to a valid object!
Updating jose
error: refs/remotes/steph/beta_gc_dev does not point to a valid object!
error: refs/remotes/steph/beta_veh_dev does not point to a valid object!
### many more remotes with the same errors ###