How to reproduce:
1. Open the "SampleScene" scene in the user-supplied project and build it for iOS
2. Launch the project on an iOS device and observe the screen

Expected result: both icons are rendered on the screen as seen in the Game view
Actual result: the icon with a Shader Graph unlit shader does not get rendered

Reproducible with: 2019.3.8f1, 2020.1.0b5, 2020.2.0a5
Could not test with: 2017.4, 2018.4 (URP/LWRP not available)

Reproduces on: VLNQA00160 iPhone 6S iOS 13.3.1

Does not reproduce with Vulkan:
N/A, Samsung Galaxy S9 (SM-G960F), Android 8.0.0, CPU: Exynos 9 Series 9810, GPU: Mali-G72
VLNQA00313, Huawei Y6 Ⅱ Compact (HUAWEI LYO-L01), Android 5.1, CPU: MediaTek MT6735, GPU: Mali-T720
VLNQA00140, Samsung Galaxy S4 (GT-I9505), Android 5.0.1, CPU: Snapdragon S4 Plus MSM8960, GPU: Adreno (TM) 320

Reproduces with OpenGLES2:
VLNQA00140, Samsung Galaxy S4 (GT-I9505), Android 5.0.1, CPU: Snapdragon S4 Plus MSM8960, GPU: Adreno (TM) 320

Reproduces with OpenGLES3:
N/A, Samsung Galaxy S9 (SM-G960F), Android 8.0.0, CPU: Exynos 9 Series 9810, GPU: Mali-G72

Notes:
1. Not reproducible on a Standalone build
2. The canvas elements with the custom shader get rendered if Postprocess is turned off on the Main Camera
3. Reproducible on Metal and OpenGLES2, not reproducible on OpenGLES3
4. Reproduced with URP 7.1.8, 8.0.1