Bloom mipchain corrupted by incorrect motion blur output

Reproduction steps:

1. Open the attached "IN-142840_BlueBloomBug_Mini.zip" project
2. Open the “Assets/Repro.unity” scene
3. Enter Play Mode
4. Make sure the aspect ratio is set to "QHD (2560x1440)" or "4K UHD (3840x2160)"
5. Select the "Sky and Fog Volume" object in the Hierarchy
6. Make sure Motion Blur is enabled
7. In the Inspector, find the “Bloom” category and ensure the "Advanced Tweaks" section is visible (otherwise, click the kebab menu and enable "Advanced Properties")
8. Enable the "Anamorphic" toggle
9. Select main scene camera and switch to a Physical mode and set its Anamorphism to -1
10. Observe the Game view

Actual result: A purple, blue, or green bloom anomaly is present
Expected result: No color anomalies are present

Reproducible with: 6000.0.15f1, 6000.0.75f1, 6000.3.16f1, 6000.4.8f1, 6000.5.0b9, 6000.6.0a5
Not reproducible with: 6000.0.14f1 (6193ad73cb06)

Reproducible environment: Windows 11 PRO (25H2)

Notes: 

• RenderDoc capture can reveal unrelated UAVs inside the Bloom mip chain (CoC in this case)