Reproduction steps:
1. Open the attached user's Project "AndroidAstcTest.zip"
2. In the Project window under "Assets/Scenes" open the "SampleScene.unity"
3. Build for Android
4. Upon the App launch rotate the screen to Landscape
5. In the lower right corner input 100 in the bottom Input Field and press "Set Alpha Power"
6. In the lower right corner press the "ASTC" Button

Expected result: ASTC Compressed Texture does not become transparent with noticeable artifacts when Alpha Power is set to 100
Actual result: ASTC Compressed Texture becomes transparent with noticeable artifacts when Alpha Power is set to 100 (See attached Results.png)

Reproduces on: 2019.4.12f1, 2020.1.9f1, 2020.2.0b7, 2021.1.0a2
Could not test on 2018.4 due to the Project breaking with downgrading

Reproducible with these devices(OpenGLES 3 and Vulkan):
VLNQA00339, Lge LG V50 ThinQ 5G (LM-V500N), Android 10, CPU: Snapdragon 855 SM8150, GPU: Adreno (TM) 640
VLNQA00024, Xiaomi Mi 5 (MI 5), Android 7.0, CPU: Snapdragon 820 MSM8996, GPU: Adreno (TM) 530

Not reproducible with these devices:
N/A, Samsung Galaxy S9 (SM-G960F), Android 8.0.0, CPU: Exynos 9 Series 9810, GPU: Mali-G72
VLNQA00316, Samsung Galaxy Note10 (SM-N970F), Android 9, CPU: Exynos 9 Series 9825, GPU: Mali-G76
iPhone 6S (iOS 13.3.1)

Notes:
-Issue does not reproduce on Gamma Color Space
-Issue does not reproduce on Standalone Builds
-Issue only occurs with ASTC Texture