My same HDMI cable works fine on ANY other device, be it a physical sky box, virgins TiVo box, my apple tv, a PC, it even works on my Xbox one for the likes of Netflix or NowTv. I even plugged it into my Xbox 360 and used sky go, bingo no issue at all.
So spending masses of money on a new hdmi cable is pointless, when it is clearly a sky app issue on the Xbox one console, or something else other than the cable, and for those of you having purchased an expensive HDMI cable is simply masking the issue.
Sky needs to look at it properly to identify and resolve the issue, which is difficult if only a few people report it.
Thanks..