"ArgumentException: An item with the same key has already been added" is thrown when the Base and Overlay cameras of a 2D camera stack use different Renderers

Reproduction steps:

1. Open the attached "IN-145480_REPRO" project
2. Open the "Assets/Scenes/SampleScene.unity" scene
3. Make sure both the Game view and the Scene view are visible
4. Enter Play Mode
5. Observe the Console

Actual result: The Console continuously prints "ArgumentException: An item with the same key has already been added"
Expected result: No error is thrown

Reproducible with: 6000.0.0b11, 6000.0.80f1, 6000.3.21f1, 6000.5.6f1, 6000.6.0b6, 6000.7.0a3

Reproducible environment: Windows 11, Ubuntu 24.04
Not reproducible environment: No other environments tested

Notes:

• Also reproduces in the Editor without Play Mode, but the error is thrown less frequently