I have a node type with its revisions set to ON I am not sure this is a bug on my copy or Drupal 6 doesn't save any revisions for CCK fields in the node and only does that for title and body?
CCK stores values against the vid, so you should be able to see the history of your fields (you can look in tables like
content_% to check that the raw data's there). Otherwise a revert would be fairly useless for most situations involving fields. Can you confirm the results of the following?
- Create new content type with revisions turned on.
- Add text field.
- Create a node of this new type (add some text to the field).
- Edit the node and update the title, body and field.
- Revert the node to its first state.