because the treehouse couldn't spawn, 95% of the events couldn't spawn properly and for the 5%, you are about to witness them past day 40 with the working one's, spawning at 0:0 since the treehouse doesn't exist.
it's the default NVIDIA PhysX 3 with NVIDIA Apex that came default to the engine. still 10 folds more stable than the first iteration of Chaos Physics that Epic Games was making.