Are you using a good quality HDMI cable to connect the Sky box to the TV?
If the HDMI cable is low quality or damaged the display will appear intermittently.
Try using a different cable and let me know if that helps?
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Does the audio stay ok when the picture cuts out, or is it also affected?
Have you got the Sky Q 4K (UHD-ready) Silver box?
The box and cable should be fine, so the problem is likely with the TV or how it is set up...
There are four HDMI ports available on the Panasonic TX-58AX802B.
However, only HDMI4 is 4K-capable. Which HDMI jack are you connected to?
Is the HDMI cable connected directly from the Sky Q box to the TV, or does it go through any other system, e.g. home theatre/sound system?
How long is the HDMI cable? It can suffer signal loss like this if it is over 10 metres long.
Are there any possible sources of interference nearby that could be affecting the signal through the HDMI cable - e.g. a cordless phone or a wireless router or fluorescent lighting?
Do you have another 4K TV that you could test the setup with?
Ok, since you have already tried a different cable then the next step would be to test the box with another TV.
Could you test it at someone else's house?
You could check with Panasonic directly at: