This worked for me!
Try and disable your X1Xfinity hot spot. I remembered, I once enabled my hot spot by turning public wifi on, my television would experienced the same pixelation glitch. This wifi "PUBLIC" option may be applied as default without you knowing that to allow other wifi devices attempting to gain excess to your wireless AP (Acess Point) causes disturbance to cable signals to your the visual on your TV set. (HDMI or regular settings) You may want to verify if your X1finity ''PUBLIC" hotspot is in enable mode, which may be set to "ON" And if so, disable your '"PUBLIC' hotspot by selecting the option "OFF". All your channel may come clear from pixelation gliching. https://customer.xfinity.com/#/settings/security/hotspot.
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