whenever an Item is submerged in a certain type of Block it will go straight upwards
That’s something I fixed on accident. I don’t know why and I don’t want to know why, but overriding setBlockBoundsBasedOnState and using a maxY value of anything smaller than 1 (even if it’s 0.999) makes it work. You can’t throw an item into a vanilla cauldron or even on lower stairs, but you can throw them on slabs because of this.