The light fluctuations were not present on every disc, but were repeatable on the two 65s i reviewed. In comparing it to other players, the level of light fluctuation of the transfer varied amonst players. For some reason, the Panasonic seems to have the most noticeable fluctuations of light level.
For reference, I encourage owners to test season 4 of six feet under. they light levels were most visible on disc 3, 4 and 5. in very detailed watching of the same scenes with other players, they light levels did not fluctuate to the point they were immediately noticeable. For example, the Samsung 5500 had a very subtle change as did the LG BD550. The Pioneer 320 did not show any fluctuation. I can't explain it any further.
It may have been the disc's authoring, but for whatever reason it was more visible with the Panasonic. It's possible it also might have been an interaction with my plasma's video settings, but it was not noticeable to the same extent with other players.