PQ issue 1 side of screen, BD only-all Sony!

[VentureRG]

Hi all. New to the site. Appreciate your advice.

I have all Sony equipment except a HD cable box/DVR from Comcast, a 40" Bravia LCD, BDP S550 and HT-SF2300, which are all connected with HDMI cables. I seem to be having noise on the left hand side of the screen while playing BD only (that is, there is no problem at all with regular DVDs). It goes from barely noticeable to somewhat distracting depending on the image/background that is displayed. It also seems to come and go depending on the day-we watched Road Warrior and Night at the Museum a couple days ago and didn't notice it at all. Tonight though it was back on every BD I tried. I even returned the Dark Knight when I first noticed the problem as I thought it was the disc. When I played the new one I exchanged it for it was fine. I've checked the connections which seem to be fine. Could it be a bad cable? Seems unusual since regular DVDs are not effected.

Thanks again for any advice or suggestions.