Hello Spine,
at the very beginning I'd like to apologize for simplifying the problem to this post's title that may not be describing the root of what is going on, so I follow specifying what we experience more thoroughly:
We've been using Unity 2022.2 with URP 14 until now and for some Skeletons in our project we use custom shaders made in ShaderGraph. To utilize URP 2D Lights, we use ShaderGraph set to "Sprite Lit" in the Graph Settings. Things have been going well.
After attempt to upgrade to Unity 2023.1 (URP 15) we observe that Skeletons with Materials using such ShaderGraph sprite shaders are rendered fine, but when the SkeletonRenderSeparator is enabled - the whole animation disappears and nothing is rendered at all. Spine shaders working well as expected.
Do you please have any idea what is going on, what had changed, or how we may fix this if we are doing something incorrect?
