What if the loss was caused by and at the leap second? e.g. imagine a self-driving car that ignored input during the leap second and crashed into a lane divider? You may have proof that the accident occurred at exactly 23:59:60.
What if the car is flying through the air aside a suspension bridge at 23:59:59 and :60, and crashes into the water a second or two later? Has the loss occurred the moment the impact with terrain becomes inevitable, or not until impact?