In the portfolio tree, when you filter for "unassigned" on a field, and filter for a specific portfolio item type, it shows the stories under the portfolio items that have been filtered out as part of the search results. Example: I filter for Features that have a custom field that is "unassigned". The result set shows the features that have the field unassigned by ALSO all stories that are children of the features that DO have the custom field assigned.

I have been repeatedly assured by the help desk at Version One that this is not a defect. While that may be true it is a user experience issue and is extremely confusing to my users. If you are searching for features that are missing a particular attribute, you should be able to have search results returned that show ONLY features, and it is very difficult to explain to users why this is a useful view when they then can't remove those stories from their filtered view.