System Information
Operating system:
Graphics card:

Broken: Blender-2.80.0-git.54ffc4e19dc4-windows64

Worked: Blender 2.79

Short description of error
The boolean modifier disables vertex groups for whatever modifiers is under it on that mesh.

I used the boolean modifier and smooth modifier for this example.
the mid section is where the vertex group is
The first picture is with the boolean modifier on top. The whole thing is smoothed when only the mid section is supposed to be smoothed.
The second picture is with the smooth modifier on top. Only the mid section is smoothed

Exact steps for others to reproduce the error
I added a cylinder and edited the cylinder to make it look like this in the picture.
I added the middle vertices of the cylinder to a vertex group named "group" and attached a smooth modifier with the "group" as the vertext group.
I added a cube
i added a boolean modifier to the cylinder with the cube as the object and set it to difference

apologies for bad english