I have (seldom) seen similar on my TV. It was during a show that I was recording on the DVR, so later I played back the recording on a different TV to check. Sure enough.. it showed up on the other TV also. So I didn't worry about it any more . . .
In my case, I first noticed this phenomenon while watching CSI live OTA via TiVo, connected to my Mits RPTV via component cables. The next day I played back that particular segment of the show though another of my TiVo's (over my network) connected to a 46" LCD in the bedroom via HDMI. Both TV's displayed the same blue cast in the same manner. I don't believe my cables were at fault. YMMV.