How to reproduce:
1. Create and open a new project
2. Import any FBX file with animations
3. Select the FBX file and change to “Animation” Mode in the Inspector
4. Add a curve in the “Curves“ section (if it does not exist yet)
5. Open the Curve Editor Window by double-clicking the curve and then close it
6. Set the Game view to “Play Maximized“
7. Enter Play Mode
8. Observe the Console

Expected result: Nothing is logged
Actual result: A “Invalid editor window of type: UnityEditor.CurveEditorWindow, title: Curve“ error is thrown

Reproducible in: 2021.3.46f1, 2022.3.53f1, 6000.0.29f1, 6000.1.0a6

Reproduced on: Windows 11 Pro (23H2), macOS 14.4.1 (M2)
Not reproduced on: No other environment tested

Note: It is enough to just open the Curve Editor once and it will always show the error until the Editor is restarted