Reproduction steps:
1. Open the “ReproProject“ project
2. Open the “Assets/Scenes/SampleScene“ scene
3. Create a new 2D Triangle GameObject (GameObject > 2D Object > Sprites > Triangle)
4. Select the “Triangle” GameObject in the Hierarchy window
5. Deactivate the “Triangle” GameObject in the Inspector window
6. Add the “Sprite Skin” Component to the “Triangle” GameObject in the Inspector window
7. Select the “Test” GameObject in the Hierarchy window
8. Add the “Triangle“ GameObject to the “Sprite Skin” Property under the Sprite Skin Test Component in the Inspector window
9. Enter Play Mode

Expected result: No errors are thrown in the Console window
Actual result: “NullReferenceException: Object reference not set to an instance of an object” errors are thrown in the Console window

Reproducible with: 2023.2.16f1, 6000.0.0b13
Couldn’t test with: 2021.3.36f1, 2022.3.22f1 (due to SetBoneTransforms not existing)

Reproducible on: Windows 11 Pro (22H2)
Not reproducible on: No other environment tested

Note: Reproduces only when the “Triangle” GameObject is deactivated, once the “Triangle” GameObject is activated, the errors are not thrown