Teleporting an entity with items in its equippable slots can prevent its server animations from functioning.

Partner Rank: 

2 

Partner Team Reporting: 

Gamemode One

Verification builds and Platforms: 

Minecraft.Windows_1.16.2003.0_x64_UAP.Release_Test

Regression build:

 Minecraft.Windows_1.16.10060.0_x64_Test

Summary:

Teleporting an entity with items in its equippable slots can prevent its server animations from functioning.

Impact: 

This is a bug that contributes to the instability of server animation. Nearly every recent map on the marketplace makes use of server animations to run important functions which makes it important they are always working during gameplay.

 

Reproduction:

I have provided an mcworld which can be used to easily reproduce the issue.

1. Import the mcworld into your game and open it. 
2. Press the button on the "Spawn entity" command block.
3. Observe the entity printing "." to chat every couple seconds.
4. Right click the entity and put a saddle into the entity's inventory.
5. Press the button on the nearby "TP to site B" command block.
6. Press the button the "TP entity to you" command block.
7. Observe that the entity has stopped printing "." in chat. This means that the server animation has stopped.

I have been able to narrow down the specific combination of factors that causes this to occur. This is listed in notes.
 
Observed Results:

The server animation which prints "." stops functioning completely after the entity is teleported.

 

Expected Results:

The server animation would continue to run under these conditions.

 

Screenshots / Videos attached:

Here is a link to a video that demonstrates me using the provided mcworld to reproduce the issue.
https://youtu.be/79A8KRC66L8

 

Notes:
If an entity:

1. Has the tick_world component.
2. Has an item placed in its inventory.
3. The player leaves the chunks near it.
4. Is teleported into loaded chunks ~200 blocks away.

This entity will now have it's BP animations and ACs broken permanently.