Bizarre missing changes (git bug?)

I ran into a strange issue that has left me scratching my head.

I have a commit in my history, that does indeed show up in my branch,  
named "sprint"

The following commands yield as follows (I've modified the output  
slightly to conceal any potentially proprietary information):

#########################
git log HEAD -p

commit 8f9effffb0dcdacd514085608e8923fbbe00ff29
Author: Name Concealed [off-list ref]
Date:   Mon Jul 14 16:19:18 2008 -0600

     commit message....

diff --git a/app/controllers/events_controller.rb b/app/controllers/ 

events_controller.rb
index 6905ba4..a0b7dfc 100644

--- a/app/controllers/events_controller.rb
+++ b/app/controllers/events_controller.rb

@@ -238,36 +238,37 @@ class EventsController < ApplicationController
    }.freeze

    RUBY_STUFF = {
-    changes...
-    changes...
-    changes...
+    changes...
+    changes...
+    changes...

diff --git a/spec/fixtures/factors.yml b/spec/fixtures/factors.yml
index 186ed73..3c76e86 100755
--- a/spec/fixtures/factors.yml
+++ b/spec/fixtures/factors.yml

@@ -2483,4 +2483,54 @@ some_branch:
    file:
    contents:
-  reliable_on:

\ No newline at end of file
+  data:
+fixture_name:
+  id: 115
+  file: Event
+  contents: behavior


#########################
git log spec/fixtures/factors.yml

... commit 8f9effff is not listed anywhere

#########################
git log app/controllers/events_controller.rb

... commit 8f9effff shows up

#########################
git branch --contains 8f9effff

   some-task-branch
* sprint


The changes in 8f9effff for app/controllers/events_controller.rb show  
up in the working copy, however the changes for spec/fixtures/ 
factors.yml are nowhere to be seen.  It's as if the history of that  
particular file diverged somehow, but I know that can't be true since  
git doesn't track files.

Anyone run into this before?  Any idea what might have caused it?   
We're a bit concerned about this because if we don't know how to avoid  
this, we no longer can feel certain that when something is committed,  
it will make it out in our release.

Any help or clues VERY much apperciated.  Thanks!

Tim