According to Wikipedia:
A set of dice is nontransitive if it
contains three dice, A, B, and C, with the
property that A rolls
higher than B more than
half the time,
and B rolls
higher than C more than
half the time, but it's not true that A rolls
higher than C more than
half the time.
In other words, a set of dice is nontransitive if its "rolls
a higher number than more than half the time" relation is not transitive.
As such .. this is a math effect