I recently experimented with smart filters and found them a very interesting and powerful tool to gain more overview about my large music collection.
Just one function does not give the results I expected: When setting filters to "Path and file " “does not contain”, there is no result given at all, regardless of the filter value. Even the scrolling search indicator bar on top of the screen does not appear. Same behaviour in album, artist or song view, as well as in smart playlists.
As all other filter settings I tried are working correctly, there may be a bug in that particular filter programming.