How to reproduce:
1. Open the user’s attached “Deadshot.zip” project
2. Add “Cable” prefab to a scene view
3. In the Scene window toolbar, select “Spline” in the Active Content dropdown (near View Tool)
4. Select “Draw Splines Tool” and add a couple of points
5. Press undo and observe the result

Expected result: One of Spline points gets removed
Actual result: All of the Spline points are placed onto the “Cable” prefab position, and an “IndexOutOfRangeException: Index was outside the bounds of the array“ error appears

Reproducible with: 2.1.0 (2021.3.0f1, 2021.3.22f1, 2022.2.14f1), 2.2.0 (2023.1.0b11,
2023.2.0a9)
Could not test with: 1.0.0-pre.8 (2020.3.47f1) (Errors after installing Splines package)

Reproduced on: macOS 13.2.1 (Intel)

Note: With some editor versions after the 5th step, all points of Spline were gone