This is a recurring problem since we connected a UHD/4K television to the UHD Swisscom box. When switching to the HDMI connection for the Swisscom box, almost always the picture flickers repeatedly until the box is restarted (At least once, occasionally twice/thrice). There is no picture flickering issue with other devices connected via HDMI connections to the TV, only with Swisscom.
When initially setting up the UHD box with this new TV, we articulated this problem and the technical support staff had us run a number of solutions that never worked. Ultimately we were sent a replacement box but this has not resolved the issue. The Swisscom UHD assistance also confirms we have everything in order in terms of connection & speed to ensure 4k/UHD picture but cannot resolve the issue