ImproBR

I have encountered the same issue. Below are the reproduction steps. I have recorded a video demonstrating how we reproduced the issue using the steps below, which resulted in the bug. The image shows a screenshot of the unexpected behavior when moving inside the Happy Ghast.
Here is the video and the image:

Steps To Reproduce:

1. Create a new Creative world with default settings.

2. Obtain a Happy Ghast Harness from the Creative inventory.

3. Summon an adult Happy Ghast using the command `/summon happy_ghast ~ ~ ~`.

4. Equip the Happy Ghast with the harness by right-clicking on it while holding the harness.

5. Use the command `/data merge entity @e[type=happy_ghast,limit=1] {Age:-24000}` to set the Happy Ghast's age to -24000.

6. Observe that the harness layer disappears from the outside view of the Happy Ghast.

7. Enter the interior of the Baby Happy Ghast by moving inside of the Happy Ghast to see the harness layer rendered incorrectly inside.

Observed Behavior
The harness layer that is visible on the adult Happy Ghast disappears entirely from the external view, making it appear as if the harness is not equipped. Upon inspecting the Baby Happy Ghast from the inside, it becomes evident that the harness layer is still rendered; however, it is not scaled correctly.
Expected Behavior
When an adult Happy Ghast is equipped with a harness and its age is set to -24000, the expected behavior is that the harness layer should remain visible and properly scaled when viewed from outside the Baby Happy Ghast. The harness should adapt to the size of the Baby Happy Ghast, maintaining its intended appearance and functionality. Specifically, the harness should not disappear and should be rendered correctly, allowing players to see the harness layer as they would expect based on the model's design.

I’ve updated to the latest version and confirmed that the same bug occurs in v1.21.10 as well. We’ve also commented on the main ticket with these detailed reproduction steps as shown here. We would appreciate it if you could provide an update on the current status of this issue.

We’ve encountered the issue with Cloning Active Flying Machines in the latest version, and it remains unresolved in v1.21.10. We opened a new ticket, but were directed here to the main one.

Below are the detailed reproduction steps along with an image of the bug. For the full reproduction video demonstrating how the issue occurs, please refer to the new ticket we opened.

MC-302629 :

Steps To Reproduce:

1. Create a new Creative world with default settings.

2. Build a simple flying machine using 2 sticky pistons, 2 slime blocks, and 1 observer.

3. Use the command '/clone' to clone the flying machine using the format: /clone <x1> <y1> <z1> <x2> <y2> <z2> <x> <y> <z> where x1 y1 z1 are the starting obsidian corner coordinates, x2 y2 z2 are the ending obsidian corner coordinates, and x y z are the clone destination coordinates.

4. Activate the initial flying machine to ensure it operates correctly.

5. Once the machine is flying, enter the /clone <x1> <y1> <z1> <x2> <y2> <z2> <x> <y> <z> command that was executed above.

6. Walk through the area where the parts disappeared for the cloned flying machine.

Observed Behavior
When a player clones a flying machine in Minecraft, certain components of the machine may fail to replicate correctly, resulting in their disappearance. Specifically, parts of the flying machine, such as pistons or slime blocks, may not appear in the cloned structure.|

Expected Behavior:
When cloning a flying machine in Minecraft, all components of the machine should be duplicated accurately without any parts disappearing. The cloned flying machine should function identically to the original, allowing players to interact with all blocks within the machine's structure as intended.

Here is the video of the full reproduction of the bug.
https://drive.google.com/file/d/1yJf-4_tLy11LFwhst3unMzUyXeprGfKm/view?usp=sharing

We have faced the same issue as well. Here is the clearer and actionable report for you to solve. The images demonstrate the bug reproduced by following steps to reproduce section.

Steps To Reproduce

• Create a new Creative world with default settings.

• Create a Copper Golem by placing an oxidized copper block, then placing a carved pumpkin or jack o'lantern on top.

• Leash the Copper Golem by right-clicking on it with a Lead in your hand.

• Run the command /tick sprint 3d to accelerate the oxidation process.

• Wait for the Copper Golem to fully oxidize and turn into a statue.

• Observe the Lead that was attached to the Copper Golem before it turned into a statue.

Observed Behavior:

When a copper golem is leashed by a player and subsequently transforms into a statue due to full oxidation, the lead (or leash) that was previously attached to it disappears entirely. This behavior is inconsistent with typical interactions involving leashed entities in Minecraft, where leads typically remain attached unless explicitly broken or the entity dies.

Expected Behavior:

When a copper golem is leashed by a player and subsequently transforms into a statue due to full oxidation, the lead should remain attached to the golem. The expected behavior is that the lead does not disappear; instead, it should either stay visibly attached to the statue or convert into a lead knot at the statue's location

This issue is not the same issue as in 300894, it is a different use case

Hello, I have encountered the same bug and created a new, detailed bug report and a new video link to reproduce the issue:

Bug Video

"Steps to Reproduce":

"1. Create a new Creative world with default settings.

1. Obtain a boat from your inventory.

1. Spawn an Enderman using the command '/summon minecraft:enderman' in the chat.

1. Place the boat on the ground near the Enderman.

1. Wait for the Enderman to enter the boat.

1. Observe the Enderman while it is in the boat and listen for teleportation sounds.

1. Note any attempts the Enderman makes to teleport while still inside the boat.",

"Environment": "Minecraft Java Edition Version 25w31a (snapshot)",
"Observed Behavior": "When an Enderman is placed in a boat in Minecraft, it exhibits an unusual behavior where it attempts to teleport while still confined within the boat. This behavior is characterized by the Enderman making the distinct teleportation sound effect, even though it does not successfully teleport out of the boat.
"Expected Behavior": "When an enderman is placed in a boat, it should not attempt to teleport or make teleportation sounds. The intended behavior is that endermen remain contained within the boat without trying to escape, as they cannot teleport while in a minecart or boat according to the game's mechanics. Instead, they should remain passive and unable to take any teleportation actions until they are removed from the boat.

Hello, I have encountered the same bug and created a new, detailed bug report and a new video link to reproduce the issue:

Bug Video

"Steps to Reproduce":

"1. Create a new Creative world with default settings.

2. Obtain a boat from your inventory.

3. Spawn an Enderman using the command '/summon minecraft:enderman' in the chat.

4. Place the boat on the ground near the Enderman.

5. Wait for the Enderman to enter the boat.

6. Observe the Enderman while it is in the boat and listen for teleportation sounds.

7. Note any attempts the Enderman makes to teleport while still inside the boat.",
"Environment": "Minecraft Java Edition Version 25w31a (snapshot)",
"Observed Behavior": "When an Enderman is placed in a boat in Minecraft, it exhibits an unusual behavior where it attempts to teleport while still confined within the boat. This behavior is characterized by the Enderman making the distinct teleportation sound effect, even though it does not successfully teleport out of the boat.
"Expected Behavior": "When an enderman is placed in a boat, it should not attempt to teleport or make teleportation sounds. The intended behavior is that endermen remain contained within the boat without trying to escape, as they cannot teleport while in a minecart or boat according to the game's mechanics. Instead, they should remain passive and unable to take any teleportation actions until they are removed from the boat.

Steps to Reproduce: