Harald Likely the problem was due to different addressable groups of the SkeletonGraphic instance and the referenced material.

I actually put the material on the same group to test and the same issue happened.
But looks like the issue isn't related to spine itself, later I had the same issue with a material on a SpriteRenderer (loaded the same way, as dependency of a parent prefab)

The spinebot suggestion of auto reapplying the material after prefab loading worked!

Thank you!

I'm currently using Spine to show Live2D artwork for each character in my game inside the UI.
I'm adjusting it inside a prefab that is marked as Addressable, also marked as Addressable all spine assets needed.
The material used is a copy of the spine built-in "SkeletonGraphicDefault-CanvasGroupStraight", and also marked as addressable.

Issue happens when I load the prefab through addressable system, spine looks like not using the linked material but instead creating a copy of it without the required shader features.
Everything else is correctly being loaded from addressables; if I just reapply the material on the loaded object it works as expected, what imply that material is the only issue.

Inspector after loading with addressable:

Inspector after just re-apply the correct material:

Thank you for your time

Thank you @Majicpanda, I had the same problem, spine was using center instead pivot for transparency order, and adding Sorting Group fixed that.