Reproduction steps:
1. Create a new project
2. Create Terrain GameObject (GameObject > 3D Object > Terrain)
3. Click on “Paint Terrain” button in the Inspector
4. Paint on the Terrain in the Scene view and observe the Assets in the Project window
Actual result: Asset icons keep disappearing when painting the Terrain
Expected result: Nothing of note happens
Reproducible with: 6000.5.0a4, 6000.5.0a5
Not reproducible with: 6000.0.66f1, 6000.3.5f1, 6000.4.0b5, 6000.5.0a3
Reproduced on: Windows 10, macOS Sequoia 26.2 (M4)