Minecarts reaching a world hole caused them to bounce off at higher speeds until the cart could build up enough speed to go through the world hole but also be bounced off creating endless minecart clones bouncing off of each other and accelerating. This created a time loop where the game would jump back a few minutes every few minutes because there was too much going on. This made a map my friends and I played on unplayable.
Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.