4th Vertex Color is always greyed out (on the viewport) + Only 8 layers of Vertex Color?

Is this a bug? Is there a workaround?
On 2.80, whenever I add a 4th Vertex Color layer, it appears as dark gray on Vertex Paint mode. This goes for all remaining colors.

When I transfer the object to 2.7 is shows all the colours. It also renders as if the layer is working, but I can’t paint on it unless I’m in LookDev mode, which is heavy on my computer.

The curious thing is: when I delete the first 3 layers, the next 3 become visible again.

Also, why the 8 layer limit? I’m colouring makeup on my avatar and I’d love some extra layers…