@MagicKyle
I can't recreate this, for something odd to happen I have to place that part of my palm on the screen not the edge, in other words my thumb will be touching most of the top of the screen, my palm will be covering half the bottom right side of the screen, if I do this while opening the home launcher I can still flip left to right, if I place more of my palm on the screen then it doesn't react but it will be covering 1/3 of the bottom part of the film, again, not the edge as on your picture/video.
The only phone were I was able to recreate this was with the Xperia T2 Ultra, but I suppose the reason its the screen size.
I took it a step further
Settings > about phone > diagnostics > test > test touchscreen
I was not able to recreate the issue, only with the Xperia T2 Ultra if I was trying to reach anything on the top left side of the screen, but not by just touching the edge.
Since the iPhone 6 has a 4.7in screen and the Z5 a 5.2in screen, that could be the cause, not a problem with the device but the size.
