Reproduction steps:

1. Download the user's attached project (“AtlasProblem.zip“) and remove the Library folder before opening
2. Open the user’s attached project (“AtlasProblem.zip“)
3. Make sure the platform is set to Android
4. Make sure the Sprite Packer Mode is set to “Sprite Atlas V1 - Always Enabled” in Project Settings > Editor
5. Select the “Assets/Atlases/default/intro_location_pan_compressed.spriteatlas” in the Project window and press "Pack Preview" in the Inspector window
6. Observe the preview that the atlas texture has no artifacts
7. Select the “Assets/Atlases/astc/intro_location_pan_compressed.spriteatlas” (which is a Variant of the default one, with compression format set to ASTC 8x8) and press "Pack preview"
8. Observe the preview

Expected result: The preview has no artifacts
Actual result: The preview has black artifacts (like the ones in the user’s attached screenshot)

Reproducible with: 2021.3.12f (Silicon), 2021.3.16f1 (Silicon), 2022.2.1f1 (Silicon), 2023.1.0a6 (Silicon)
Not reproducible with: any Intel build of the Editor, 2023.1.0a24 (Silicon)
(2020.3 does not have a Silicon version available, not a "true" regression)

Reproduced on: Mac Mini M1 (2020)

Notes:

• Does not reproduce when the format is set to ASTC 5x5, ASTC 10x10, ASTC 12x12, any of the ASTC HDR formats or any non-ASTC compressed format
• Does reproduce when the format is set to ASTC 6x6 or ASTC 4x4, but artifacts have different sizes or color
• Does not reproduce when the ASTC atlas is a Master atlas, only when it's a Variant atlas