Reproduction steps:

# Open the attached project
# Open the “/Assets/Spline.unity” Scene
# Select the “Spline” GameObject in the Hierarchy window
# Enter the Spline Edit Mode and select one of the knots of the “Spline” GameObject in the Scene View
# Press the “Reverse Spline Flow” button 10 times in the Element Inspector and observe the changes after each press in the Scene View

Expected result: The Spline Flow gets reversed without any errors and shape changes
Actual result: After the 3rd press - Quaternion To Matrix conversion errors appear, and after the 8th press or more - the shape of the spline begins to change erratically

Reproducible with: 2.0.0, 2.1.0 (2021.3.13f1, 2022.1.22f1, 2022.2.0b15, 2023.1.0a18)
Couldn’t test with: 1.0.0-pre.8 (2020.3.41f1), 1.0.1 (2021.3.13f1, 2021.1.22f1) - Spline package errors

Reproducible on: Windows 10 (21H2), M1 MacOS 13.0 (22A380)