[unity] Spine/Skeleton Lit shader shows incorrect light/dark changes

[HaraldCsaszar]

As reported on the forum:
http://esotericsoftware.com/forum/Sudden-Light-Dark-Change-In-Skeleton-Lit-Shader-11935

Reproduction package, with additional modifications needed:
FMfcgxwCgfsLvdcqwpbPplQZjJFwvNNx

Occurs in the repro-scene when

1. [update: NOT NEEDED according to forum] a SpriteRenderer (trees) in the scene is assigned any one of the Spine shaders [update: or Standard shader according to forum] and
2. multiple MeshRenderers (duplicated medikit) with Spine/Skeleton Lit shader are in the same scene and
3. one of the MeshRenderers is moved around in the scene in Z direction,
4. observe some of the MeshRenderers becoming lighter in Game view (does not occur in Scene view)

Also, Spine/Skeleton Lit produces the same lighting artifacts when assigned to the trees (as in the repro package) - trees change color when the single medikit is moved in Z direction.