Steps to reproduce:

1) Download attached project and open in Unity
2) Make sure Vulkan is the only Graphics API in the Player Settings
3) Build and Run project on a device
Note:
Observe water splashes rendered in black (check attached "repro.gif")

Reproduced with:
2019.1.0b3
LWRP package version: 5.3.1

Devices under testing:
Reproduced with:
VLNQA00013 Samsung Galaxy S6 Edge+, GPU: Mali-T760, OS: 7.0

Not reproduced with:
VLNQA00129 Nvidia Shield, GPU: NVIDIA Tegra, OS: 7.0
VLNQA00220 Samsung Galaxy Note9, GPU: Mali-G72, OS: 8.1.0
VLNQA00218 Samsung Galaxy Note9, GPU: Adreno 630, OS: 8.1.0
VLNQA00222 Google Pixel 2XL, GPU: Adreno 540, OS: 9.0