This is just a guess...

The number of horizontal lines cableTV, broadcast channels, and VCR's put out is fewer than what DSS or DVD's put out typically. The TV is smart enough to display as many as the signal contains. So the reason you only see the blue bleed when using your SAT is that the sat's signal is making the TV show more picture, and the flaw is at the extreme of the TVs higher resolution ability.

My guess is that your TV's scanning circuitry is flawed or slighly broken. I'd suggest trying the DSS on another monitor. If the blue doesn't show up on your old TV, and you can see the same "bottom edge" of the DSS picture, then the flaw is with the new TV.

I'd get them to service it. Take advantage of the warranty.

Just a guess.

Dave