Thanks for reporting and sorry for the trouble.
The clean bugfix will take a bit more effort, so we have created an issue ticket here:
[unity] Mask interaction materials cause unnecessary batches · #1769
We will let you know once the issue is resolved.
If you are in a hurry you can change the lines 466-468 of SkeletonRenderer.cs from this:
if (materialsChanged && (this.maskMaterials.AnyMaterialCreated)) {
this.maskMaterials = new SpriteMaskInteractionMaterials();
}
to the following:
if (materialsChanged && (this.maskMaterials.AnyMaterialCreated)) {
if (Application.isPlaying) {
this.maskMaterials = new SpriteMaskInteractionMaterials();
}
}
This will solve the problem for most cases.