I believe it thinks the same episode appears within 28 days so it did not record.
If you had set the season pass to record All (including duplicates), it would record them all, even though they may be reruns or episodes with little or no guide data.
Original S1 (Recycle Heaven)
Series 2 (PLS, sold)
TiVo HD (XL, PLS, "652")
Juliet Basic (4XL, PLS)
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!