Hi, my new Duo 4K is 'stuttering' on changing channels. It generally switches cleanly between SD or between HD channels, (as any TV or STB would do), but from SD 720 etc to HD1920) there is a flash of picture, then a black screen for a second or so before a picture emerges, which is driving me nuts.

Is this something I can fix, or if it is an inherent issue? Do other Vu+/Duo 4K see this behaviour?

Many thanks