There's an item on the front page of the 4NCL web site (dated 9/4) which is probably relevant:
In line with FIDE regulations all calculations are based on the October 2008 list, which was the active list when this season's league started.
Results for the league so far have been submitted in two batches. Rounds 1 to 4 for rated players went into the January list and are on the web here.
Rounds 5 and 6 for rated players went into the April list and are here.
Rounds 7 onwards for rated players and all results for unrated players will be submitted after round 11 finishes in early May, and these will be included in the July list.
If my understanding is correct, the new FIDE rating regulations allow games against unrated players to be rated and for unrated players to get ratings from Swiss System events in which they play nine or more games (previously only all-play-all tournaments worked in this way). So it looks to me as though all of this season's 4NCL results have been resubmitted to take account of the unrated players, but this has resulted in rated games being duplicated.
My guess is that the duplicated games need to be removed, and then everything will sort itself out.
Here's Stewart Reuben's summary of the changes to the FIDE rating system, which I managed to track down on the ECF site:
http://www.chessuk.org/archive12-05-09/ ... _mar09.htm
Some of this has been overtaken by FIDE's apparent backtracking on changes to the K factor, but I think the rest still stands.