Swapping custom_hit_test components is unreliable

Partner Rank:

2

Partner Team Reporting:

Everbloom Games

Verification builds:

1.16.100.55

Summary:

Swapping custom_hit_test components is unreliable. Sometimes it seems to not synchronize correctly to the client, either not adding the new hitboxes, or not removing the old ones. Also, it seems to cause additional hitboxes to appear near 0.0 0.0 0.0 (positioned as if the entity was located at the origin)

Impact:

This makes custom_hit_test hitboxes static, unable to be changed during gameplay (or at least, forcing us to accept that the hitboxes might be incorrect if we swap them).
This is also unfortunate because the most logical way to get around MCM-1091 is to swap custom_hit_test components, and it doesn't achieve the desired effect either.

Repro Steps:

1. Open the provided world
2. Enable rendering of entity bounding boxes (/bounds)
3. Head to the blue-floored chunk with a diamond block-looking entity in a fence, a lever and a button
4. Look at the yellow hitbox around the diamond block
5. Flip the lever to be in the "Up" position, and then back "Down".

Expected:

After flipping once:

A yellow hitbox should have appeared 5 blocks above, and the old hitbox should have disappeared, giving the illusion of the hitbox "moving" up 5 blocks along with the model.

After flipping twice:

The yellow hitbox should have appeared to move "down" to its original position

If you press the "Teleport to itself" button in either of the states, it should realistically not change.

Observed:

Honestly I can't describe what's going on with the hitboxes, all I can say is that it goes from 1 to 3 to 4 to 2 where it should never be more than 1. Teleporting the entity to itself messes it up even more. The attached video should illustrate the issue, and the attached image shows all 4 hitboxes at once, labeled.

**

Screenshots/Videos attached: Yes/No

Yes: https://youtu.be/pVrmt4xEJt4 

Regression Builds:

This has always occurred, since the introduction of custom_hit_test

Notes:

Just to be clear, these are all active hitboxes that the player can interact with, they're not just an artifact of the hitbox renderer (even though, I assume there's some optimization that makes player and projectile interactions with hitboxes discard entities whose "feet" are far enough away, so the hitboxes at the world origin don't do anything; but if the entity were closer to the origin, you would be able to interact with them)