If I remember correctly, this was a bug in Portal 2003 that was eventually
corrected. Perhaps that fix was not ported into the MOSS implementation.
I don't remember all the details, but thought I would bring it up.

No AD changes  actually trigger  anything btw...what should be occuring, is that
during the incremental  crawl, when we do a "Change Check" on the target object,
it should see that the property was in deed changed, and update  the profile. If
I'm reading you correctly, you're stating that changing the manager  property is
not causing the profile  to be updated at the next incremental crawl, but
changing a different attribute of that user  object in AD, causes the manager
property to then be synched during the next crawl correct?

What is an example of the other fields that are triggering the update  on
your system?

That is correct other fields that are changed in AD will trigger  the
refresh of the SharePoint user  profile. In our case, the telephone
number was the field  we changed in AD. Interestly this field has a
policy setting  of required and manager  is optional. The manager
field's policy setting can't be changed to required. Can anyone shed
some light on what this means.