Hi, Dnorton77
It may be a bouncy switch or noise, Whats your De-Bounce setting in Config, General Configuration Screen, Top right.
Try increasing it to 1000 - 2000, See if that helps.
Check your wiring, Made any changes recently.
The "but it is a 50 50 chance", Get a Double Headed Quarter, That will improve your Odds ?
Hope this Helps, Chip