The Bug:
The end obsidian platform resets every time entities go through the end portal, which can cause blocks to be deleted.
This notably results in containers like chests or shulker boxes which might contain valuable items within them being deleted.
Steps to Reproduce:
Enter the end by using an end portal.
Place some blocks on top of and around the obsidian platform that you spawn on.
Take note of the blocks that you've just placed.
Run the "/kill" command.
Enter the end once again and attempt to locate the blocks you just previously placed.
Take note as to whether or not the end obsidian platform resets every time entities go through the end portal, which can cause blocks to be deleted.
Observed Behavior:
The end obsidian platform resets every time entities go through the end portal, which can cause blocks to be deleted.
Expected Behavior:
Blocks on the end obsidian platform would not be deleted every time an entity goes through the end portal.
Code Analysis:
Code analysis by @unknown can be found below.
The following is based on a decompiled version of Minecraft 1.18.1 using MCP-Reborn.
net.minecraft.world.entity.Entity.java
public abstract class Entity implements Nameable, EntityAccess, CommandSource {
...
public Entity changeDimension(ServerLevel $sl) {
if (this.level instanceof ServerLevel && !this.isRemoved()) {
...
if (portalinfo == null) {
return null;
} else {
...
if (entity != null) {
...
if ($sl.dimension() == Level.END) {
ServerLevel.makeObsidianPlatform($sl);
}
}
...
If we look at the above class, we can see that when an entity enters the end portal, the makeObsidianPlatform()
method is called. This method completely regenerates the end obsidian platform (including the space above), causing blocks previously placed at its position to be deleted.
Related issues
is duplicated by
relates to
Attachments
Comments

Intended. The spawn platform and the air above it are reset each time someone enters the end.
Tip: Don't place your chests on it.
Oh okay thanks.
But isn't it still a bid stupid, that it resets everytime?
If it didn't reset, then someone could fill it with blocks and when you went through, you'd suffocate.
Nether portals have a bit of space in them already so that can't happen with them.
Oh wauw, hadn't thought about that. Well thanks for clarifying this for me.
ye if this is a permanent thing.. pls put it in the Wiki. It is very disappointing.
Just lost the best shulker box I had, thanks mojang, really cool. Btw, I know this isn't completely a bug, but still, your game is already full of unsolved bugs.
Hi! I'd like to request ownership of this report.
Can confirm in 21w05b.
Can confirm in 21w10a. Video attached.
Can confirm in 21w17a.
Can confirm in 1.17.

Can confirm in 1.17.1 Pre-release 1.
caused by the fix for MC-123155
Can confirm in 1.17.1.
Relates to MCPE-52483.
Why is this a bug? It is so people can't trap the end, by removing the platform and letting you fall in the void, or by soffocating you, intentional or not intentional. It also allowed for farming obsidian this way, which is used by many players. In my opinion this should be intentional game design. (If you want to fix it you could only generate the platform and remove the blocks once, when they enter.)
This is an intended feature. Not a bug. The solution is to not use the obsidian platform as an area to put your stuff.

Newer players might not know this. Also this has an assigned Mojang Priority, so it is considered a bug.
Also, where is the source of this not being a bug?
I can see how this is a way of preventing "spawn killing", by breaking the platform, or filling its space up. However, it makes more sense to only set the obsidian blocks if there's air, and only set air anywhere on the platform, if there's no air on the platform (and if there is, to move the player to it).
I am able to confirm this behavior in 21w39a. Here are some extra details regarding this problem.
The Bug:
The end obsidian platform resets every time an entity goes through the end portal, which can cause blocks to be deleted.
Steps to Reproduce:
Enter the end by using an end portal.
Place some blocks on top of and around the obsidian platform that you spawn on.
Take note of the blocks that you've just placed.
Run the "/kill" command.
Enter the end once again by using an end portal and notice how some blocks that you previously placed have been deleted.
Observed Behavior:
The end obsidian platform resets every time an entity goes through the end portal, which can cause blocks to be deleted.
Expected Behavior:
The end obsidian platform would not reset every time an entity goes through the end portal, which wouldn't cause blocks to be deleted.
This horrible behavior. I've been playing for years and didn't know this, and having a couple shulker boxes of stuff that took hours to create vanish without warning is a bug, esp. when there is no cause to clear the blocks...the platform had plenty of space to spawn players. The fact that this was opened 9 years ago means "Normal" priority is to ignore it.
I just lost 3 SO MANY hours of work in mining and enchanting to this bug. How has this not been addressed? This is absolutely ridiculous.

Present in 1.19-pre4.

Present in 1.19-pre5.

Present in 1.19-rc1.

Present in 22w24a.
this is intended because the end has a fixed spawnpoint and you would suffocate if the obsidian platform and 2 3 by 3 layers above it wouldnt reset. i would rather be happy about a basicly infinite obsidian farm because of that.
Is it intended that when I set a shulker box full of high tier items down and another player comes through and it vanishes? That's a bug. clear the space around the head of the incoming player if you must and regenerate the obsidian, but not the whole platform.
It also doesn't need to do that every time; as long as it can find a place with block below feet and air at head, it shouldn't regenerate; if there's none, it only needs to fill those 2 blocks, not destroying everything.
I think the blocks should drop as if mined by a player instead of being deleted
@unknown, this game mechanic isn't working as intended as per the assinged "Mojang Priority" on this ticket. In other words, Mojang Studios have recognized this to be a valid problem.

Can confirm in 23w03a

Can confirm in 23w04a

Can confirm in 23w05a

Can confirm in 23w06a

Can reproduce in 1.21 Pre-1
EDIT: According to Kingbodgz' tweet (https://x.com/kingbdogz/status/1795823127362154962) this cannot be reproduced in 1.21 Pre-1