Minecraft wiki entry for End_of_light_mob_farms, associated text: Update suppression is a glitch that allows the player to update certain blocks without causing updates to another. The main use is to make sliced portals which is a key component of the farm. It is used to place blocks at impossible block states usually done by stack overflow. If the update is cause directly by a player, it will not crash the game. But if it is done by natural means, it will crash the game. Using powered rails is the method of choice for most players. This does not work only in Java Edition 22w11a, when the update order was changed from a stack to a queue. The bug was fixed in the next snapshot, 22w12a[1].