SharedPreferences.onSharedPreferenceChangeListener not being called consistently

I'm registering a preference change listener like this (in the onCreate() of my main activity):

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);

prefs.registerOnSharedPreferenceChangeListener(
   new SharedPreferences.OnSharedPreferenceChangeListener() {
       public void onSharedPreferenceChanged(
         SharedPreferences prefs, String key) {

         System.out.println(key);
       }
});

The trouble is, the listener is not always called. It works for the first few times a preference is changed, and then it is no longer called until I uninstall and reinstall the app. No amount of restarting the application seems to fix it.

I found a mailing list thread reporting the same problem, but no one really answered him. What am I doing wrong?