Reproduction steps:
1. Open the attached “inputsystemnull.zip” project
2. Double click on the “NewActionMap.inputactions” asset from the Project Window
3. Select the “Control” Action Map in the Input Actions Edit Window
4. Duplicate it twice by pressing ‘CTRL+D’ twice
5. Undo the duplication by pressing ‘CTRL+Z’ twice
6. Observe the Console Window

Expected result: No exceptions are thrown
Actual result: “NullReferenceException: Object reference not set to an instance of an object” is thrown

Reproducible with: 1.8.0-pre.2 (2022.3.37f1, 6000.0.10f1), 1.8.2 (2022.3.37f1, 6000.0.10f1)
Not reproducible with: 1.8.0-pre.1 (2021.3.40f1, 2022.3.37f1, 6000.0.10f1), 1.8.0-pre.2 (2021.3.40f1), 1.8.2 (2021.3.40f1)

Reproducible on: Windows 10 (User reported), Windows 11
Not reproducible on: no other environment tested

Notes:
- After undoing the Actions Maps, the NullReferenceException also gets thrown when docking the Input Actions Edit Window
- The issue does not reproduce if the latest duplicated Action Map is unselected before performing the undo action