System Information
Operating system: Linux-4.15.0-55-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.26

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-24 14:22, hash: rB507ffee6e1f4
Worked: (optional)

Short description of error
Viewport Vertex color doesnt work in sculpt mode, the model turns black

Exact steps for others to reproduce the error
Create a sphere, go to vertex paint and paint.
Go to solid mode, and in Viewport shading, change the color to 'vertex'
then go to sculpt mode, and your sphere than you vertex painted on should turn black