If you edit a Smart Playlist to change "Match all" to "Match any," and then go back to edit the list again, the Match option has reverted to Match all. If you click OK without changing the Match option, the Smart Playlist will change to reflect Match all.
Use Software Update to update to iTunes 7.6 or later to resolve this issue.
If you're not able to update and you want to "Match any" of the rules, then edit the Smart Playlist again and choose "Match any" again.