a peace of a post from ruud gives pretty much so I place it here:
I in fact changed the precedence of NOT in 4.10 (it was broken before), but clearly not good enough yet. The 'not 0 and not 1' was effectively being evaluated as 'not (0 and not 1)', which obviously is not the same thing at all...
I've fixed this in the final build (due out soon).
Thanks for the heads-up on this one!