What's the layer for the block?
Check the layer shown in the block's property manager.
You may have to update the block for the required layer (or change the block's current layer accordingly).
It looks like when I changed the blocks layer in the drawing, nothing happens. When I would output to pdf, the colors would show up correctly, but they don't do that anymore.
I'm on 2018 SP1
As an aside, when you get this issue ironed out:
So others can have a standard method to access the blocks, I recommend storing them in a network share under a root folder of common SolidWorks data (that's outboard of SW's numbered installation folders)
Using File Locations, determine where your Design Library is and go there in Windows Explorer.
Create a shortcut of your blocks folder here:
And it will be available in the Design Library tab in SW:
Drag and drop your blocks from here.
Creating this shortcut for others is all that needs to be done to get them this common access.