Entity spawns at a weird block offset (using Mythicmobs and ModelEngine4)

[siulung201314]

Spark link

N/A

Expected behavior

1. Entity spawns at a correct block offset
2. Entity does not shift vertically after unloading and reloading it/restarting the server.

Observed/Actual behavior

1. Entity spawns at a weird block offset.
2. Entity shifts vertically after unloading and reloading it/restarting the server.

Steps/models to reproduce

1. Create a MythicMob with NoGravity: true

2. Spawn the entity using Mythicmobs eggs

3. Entity spawns at a weird block offset.

Or

1. Create a MythicMob with NoGravity: true

2. Spawn the entity using command

3. Restart the server

4. Notice the entity is now higher/lower than before

Purpur version

This server is running Purpur version 1.21.10-2518-HEAD@ffe2f80 (1970-01-01T00:00:00Z) (Implementing API version 1.21.10-R0.1-SNAPSHOT)

• You are running the latest version
  Previous: 1.21.10-91-9934c17 (MC: 1.21.10)

Agreements

• I am running the latest version of Purpur available from https://purpurmc.org/downloads.
• I have searched for and ensured there isn't already an open issue regarding this.
• I ticked all the boxes without actually reading them
• My version of Minecraft is supported by Purpur.

Other

There is some related information about the issue.
https://discord.com/channels/213109157983813633/1409006269439803412/1428435672305504477
At first, we have reported the issue to Ticxo, the author of ModelEngine 4.
Ticxo has since tested the issue and uploaded two videos demonstrating that it only occurs on Purpur, not on Paper.
I have also verified this behavior on both Paper 1.21.10 and Purpur 1.21.10, and the issue persists exclusively on Purpur.
We are therefore reporting the issue here for further investigation.

[Krakenied]

Is it also a thing with the default Purpur config?