Steps to reproduce:

1. Download and import the attached repro project
2. Open the Scene "SampleScene.unity"
3. In the lighting window, ensure that Filtering is set to "Advanced"
4. Ensure Indirect Denoiser is enabled and set to any option (Optix, Radeon, Open Image)
5. Ensure that there is guassian filtering enabled for Ambient Occlusion
6. Generate Lighting

Observed:

- Note that the lightmapped result will display bright halos around intersecting, lightmapped geometry. This can be confirmed using the "baked lightmap" scene view

Expected:

- There should no be bright halos around objects or underneath where dilation is present.

Notes:

- This appears to be related to some interaction between denoising of indirect and guassian filtering when ambient occlusion is composited. The issue is reproducible using any denoiser, but only when guassian is used for filtering. The issue also does not reproduce when using GPULM. The issue reproduces in HDRP, URP and BiRP.
- Only reproduces with HDR light intensities.
- Reproduces in: 2020.1.0a12, 2020.1.0a24, 2020.1.0b7, 2020.1.1f1, 2020.1.9f1
- Does not reproduce in: 2019.1.14f1, 2019.2.21f1, 2019.3.16f1, 2019.4.12f1, 2020.1.0a3, 2020.1.0a9, 2020.1.0a11