Wasn't another Nikko going down was it? Kev's went tu somewhere before the 35yd'er on the last lane before the 2nd section...unusual since they are so rock solid. But then I guess with that many being used so much for so long, a failure now and then isn't something unusual.
Don't sweat the error Paul... just stick it in your routine that when your going past a turn, to make a mental note and get it back down a turn as soon as you finish. Once stuff is firmly in your routine, unless your distracted, it normally sticks there. Next time you'll know you can make amends.