Strange Mesh Object in Editor

Grelle

Hello there.
Our animators meet strange thing.
They create prefab with spine object, set it up (like usual, thousand times before), and - suddenly - some strange Mesh Object appears.

You see, some Bears doesnt have this object. This Bears have "None" in mesh field or "Skeleton Mesh" (then you open prefab). It is usual behaviour.

And Problematic bears have this object as Mesh. And it is object is not exist in hierarchy.

So, my questions are:

What is this new mesh object? Is its appear is bad?
Why it appears? What settings make it appears?
How to make all things work as before? We had Spine 3.8 before, and updated it to 4.1 on this project; so it is first wotk with 4.1. And I dont sure version has meaning

Harald

@Grelle Adding the procedurally generated skeleton mesh to the prefab fixes the issue of the prefab always being marked as "Override" (as changed) even though nothing has changed. The meshes are automatically removed before building the executable via a pre-build step, so build size or load time does not increase.

Unfortunately it's a tradeoff and not a perfect fix without drawbacks. See this issue ticket here:
EsotericSoftware/spine-runtimes1273

You can configure the behaviour via the Unity Edit - Preferences - Spine settings, in section Prefabs:
https://esotericsoftware.com/spine-unity#Spine-Preferences

Grelle

@Harald

It is our first Spine 4 project; on Spine 3.8 this meshes didn't appear. So we just worried about this; I glad to hear this is correct behaviour, and we don't need to worry or fix this. Thank you!!