I've also tried multiple times and am not able to reproduce it either.
I'm also not sure I can follow exactly what is going on in the video, as we don't see how keys are sustained etc (assuming the sustain pedal) and the switching is very fast -- there is some weird noise going on, but it's hard to hear exactly what it is.
Does it happen only with the samples you showed or can it happen also when switching between e.g. acoustic pianos or electric pianos?