I have a frequent problem with Alfred failing to find text files (MEL script text file actually) that are in one of the specified folders and added manually to the searched types:
http://dl.dropbox.com/u/7990437/mel_alfred.png
http://dl.dropbox.com/u/7990437/missing%20mel%20files%20in%20alfred.mov
It's happening all the time and it's really hit and miss so there's no way for me to figure out what the cause is.
I should note that Spotlight finds it fine