Steps to reproduce:
1. Open the attached user's project "Frustum.7z"
2. Open the "OutdoorScene.unity" Scene and enter Play Mode
3. Observe the Game View

Actual results: directional light shadow cascades are visibly clipped. Shadows disappear in portions of the view that fall outside what a symmetric frustum would cover
Expected result: directional light shadow cascades are not clipped

Reproducible with: 6000.0.70f1, 6000.3.9f1, 6000.4.0b11, 6000.5.0a8

Environment tested: Windows 11 25H2

Notes:
-Using nonObliqueProjectionGetter didn't solves the problem. Modifying the cascades distance and the shadow distance in the shadow override of the Volume works as a workaround.
-The camera's frustum is modified via the Frustum component found in the "camera" GameObject
-Change the if condition in Frustum.cs "UpdateFromViewport" to enable the use od nonObliqueProjectionGetter