I am terribly sorry that no one has been able to answer your thread, but it does seem that you have been the only person who has posted here about this type of odd repeated button pressing, so it may be that no one else including me knows why this is happening or what can be done to correct this.
So really the only suggestion I can give is to give a call to Nintendo's 1-800-255-3700 (6 am ~ 7 pm Pacific, everyday) Customer Service number, or use their webform to contact them, and see if any of the service representatives have heard of this, if not, perhaps pass along this to proper departement to see if they can recreate the problem, and then perhaps work on some type of update to fix this.