Operating system: Linux-5.8.0-7630-generic-x86_64-with-glibc2.32 64 Bits
Graphics card: Quadro RTX 6000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.32.03
Broken: version: 3.0.0 Alpha, branch: master, commit date: 2021-04-29 07:54, hash: rB868c8e8617d0
Worked: (newest version of Blender that worked as expected)
Short description of error
When vertex selection (or face selection) is used in either vertex paint or weightpaint mode the state of hidden geometry is not synchronized but overwritten by some specific state on this object. That makes it impossible to paint on using vertex selection. Joining the mesh into a new object did not fix the issue.
Exact steps for others to reproduce the error