How to reproduce:
1. Create and open a new project
2. In the Project tab, in the “Assets” folder, create a new Render Texture (Right-click → Create → Render Texture)
3. In the Hierarchy tab, select the “Camera” GameObject
4. In the Inspector tab, under the “Camera” component, assign the created Render Texture to the “Target Texture” (or “Output Texture”) property
5. In the Project tab, delete the Render Texture
6. Move the mouse around the Editor, hovering over Game window
7. Observe the Console tab and Editor

Actual result: A ghost window and multiple errors appear
Expected result: A ghost window and multiple errors do not appear

Reproducible with: 2023.1.0a5, 6000.0.72f1, 6000.3.12f1, 6000.4.1f1, 6000.5.0b2, 6000.6.0a2

Reproducible on: macOS 15.3.2 (24D81) (M1 Max)
Not reproducible on: No other environment tested

Notes:

• After following the reproduction steps, deleting the “Camera” GameObject triggers multiple “NullReferenceException” errors
• The reproduction results are inconsistent: some versions produces only errors, whereas others only trigger the ghost window
• In the 6.4, 6.5 and 6.6 streams, both the ghost window and the errors appear simultaneously only if the scene contains two Camera GameObjects