pixelated

Hi guys, a Zgemma H2H which i setup for the inlaws has started to cause some pixelations to the image on sky movies action, comedy and family channels but only on HD. the sound all plays fine without any breakup but the image costantly breakup and pixelate. The splitter is the a technetix...

So I got vm cable to work on my VU+ box and everything works fine except Sky Movies Action which is heavily pixelated. All other channels work fine. What I have tried: Different splitter same issue Different cables same issue Different providers same issue Checked all connections connected...