Steps to reproduce:

1) Download attached project and open in Unity
2) Make sure Graphics API is set to GLES2 in the Player Settings
3) Build and Run "OfflineTrainingScene" on a device

Expected result: No visual artefacts on the screen (check attached image "expected.png")
Actual result: Visual artefacts on the screen (check attached image "actual.png")

Reproduced with:
5.6.5f1, 2017.1.3f1, 2017.2.1p1, 2017.3.0p1, 2018.1.0b1

Devices under test:
Reproduced with:
0154 || Samsung Galaxy Note 8, OS: 7.1.1, CPU: Samsung Exynos 9 Octa, GPU: Mali-G71
0131 || Huawei P9, OS: 7.0, CPU: HiSilicon Kirin 955, GPU: Mali-T880

Not reproduced with:
5007 || Nvidia Shield Tablet, OS: 6.0, CPU: nVidia Tegra, GPU: GeForce ULP MP192
000037 || iPad Mini 2

Note: Works fine using GLES3 or Vulkan Graphics API
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Fixed in:
2018.3.0a6