Lowering Cloud Layer channel opacity beyond a certain threshold results in graphical artifact

Steps to reproduce:

1. Download and open the attached project (Bug-HDRP-CloudLayer.zip)
2. Select the Sky and Fog Volume
3. In the Cloud Layer, check one of the opacity channels (Opacity R, B, G, or A)
4. Lower the opacity value
5. Switch to the Game view (or look directly overhead)

Expected result:

• Procedural skybox looks clean, regardless of the opacity value used

Actual result:

• A bright, dot-like artifact is visible directly overhead, where the cloud layer converges (see attachment CloudOpacity-0.1.png)

Notes:

• Reproducible in Unity 2021.3+
• Reproduces in HDRP only
• Only reproduces when tweaking individual Opacity channels; does not reproduce when tweaking the global Opacity parameter