Steps to reproduce:

1) Download attached project and open in Unity
2) Make sure Graphics API is set to Gles2
3) Build and Run project on a device
4) Select effects in that order: DepthOfField, Grain, LensDistortion, Vignette
5) Click on Run! button
Observe: Black screen when Depth of field effect is active

Expected result: No black screen

Reproduced with:
2018.3.0b12, 2019.1.0a10

Devices under testing:
VLNQA00216 Razer Phone 2*, OS:8.1.0, CPU:arm64-v8a, GPU:Adreno (TM) 630
VLNQA00175 Samsung Galaxy Note9, OS:8.1.0, CPU:arm64-v8a, GPU:Mali-G72

Not reproduced with:
VLNQA00212 iPhone Xs, SoC: A12, iOS: 12.0