wow some heel that driver has, only thing i could put it downt o is a mouse jump, seen this happen to me and i put it down to having crumbs,shrapnell or some other alien speck of dust which affects the sensor.
only happens some times and i always notice it so havent suffered from it but this may not be the case with you just that that is the only p;lausible answer i can think of.
regards
ladzrls