Blue & red vertical bars in the middle of the display

[blu-bee]

We got our first HD LCD almost a month ago now and have been really happy with it, except for occasional blue or red vertical bars running down the middle of the display. Now, this only happens it seems on certain cable channels (esp. SD HBO channels) and never happens on the HD channels or with a DVD or BD. BD looks perfect, clear and hyper-real.

I'm pretty certain this is simply the cable service on certain channels, i.e. the signal is dirty and causes this anomaly. It's interesting because if you 'rewind' you can see the bars again in the same spot.

display: Samsung LN46A550
cable service: Time Warner w/ HD DVR (Moxi) via DVI -> HDMI cable

I'm thinking of seeing about swapping out the DVR, see if they have one with straight HDMI connectors now.