How to reproduce:
1. Download the package "weathermaker.unitypackage" from the Google Drive link and import it to a new Unity project
2. Build the "DemoScene" on iOS and deploy it
3. Tap the dropdown menu under the checkbox labeled "Sleet" and tap on any option

Expected result: the clouds appear in the sky and the shader compiles
Actual result: the entire sky is pink, and no shader compilation errors are thrown

Reproducible with: 2017.4.38f1, 2020.2.0a3
Could not test with: 2018.4.19f1 due to the app freezing

Reproduces on:
VLNQA00160 iPhone 6S iOS 13.3.1
VLNQA000069 iPhone X iOS 11.3.1
iPhone 7 Plus, iOS 12.0
iPad 7th gen (iOS 13.2.2)
iPhone 7 (iOS 12.3.1)

Does not reproduce on:
N/A, Samsung Galaxy S9 (SM-G960F), Android 8.0.0, CPU: Exynos 9 Series 9810, GPU: Mali-G72
VLNQA00220, Samsung Galaxy Note9 (SM-N960F), Android 8.1.0, CPU: Exynos 9 Series 9810, GPU: Mali-G72
VLNQA00024, Xiaomi Mi 5 (MI 5), Android 7.0, CPU: Snapdragon 820 MSM8996, GPU: Adreno (TM) 530

Notes:
1. The issue could be related to the "Fullscreen" custom shaders the clouds use.
2. Not reproducible on OpenGLES3, in Play Mode and in MacStandaloneBuild.
3. Not reproducible with OpenGLES3 and Vulcan on Android