Each entry in the playlist seems to be last played at 01:00am and most of the entries that should be there are missing.
Selecting the entire library node and using the column header to sort it seems to display the expected results.
Please note that many entries are still tagged as last played at 01:00am, don't know if it's correct or what. Actually it seems strange to me.
I attached some screenshots of the issue below.
I'm using Windows 7 x64 and I recently upgraded from version 3.
I'm using the iTunes plugin to sync music and playlists to an iPhone.
Should I attach a debug log?
Screenshots:
[WRONG] Playlist sorted by Last Played Descending:

[CORRECT?] Entire Library, ordered by Last Played using column headers:

Playlist Settings:

