It wasn't actually that exact amount. It was "about 12 tons", and somebody did the 12000 kg / 29g calculation and used the answer with way too many significant digits. Probably the reporter trying to make the 12 ton number relatable.

(You might object that KitKats usually weigh 40g. So these were probably the new KitKat Icon F1 chocolates, which weigh exactly 29g.)

My brain went here too. I'm guessing that one box missed the truck (either it was damaged during loading or had a manufacturing defect), so a full shipment is 3 x 3 x 23 x 2000. So my SWAG:

1 box = 3 x 3 x 23 bars

1 pallet = 10 x 10 boxes

1 truck = 20 pallets

How did they come up with an odd number when individual packs are an even number of bars? (And, I imagine, cartons are a multiple of dozens of packs.)