I thought this never happened. The cards need to copy each other's VRAM to have the GPU's process alternate workloads, or there'll be synchronization issues.Ya I heard about the 970 fiasco. Apparently I've heard the VRAM doesn't double when in SLI, too, but I haven't even bothered to google that..
I don't think many people fit a use case where they are going to need the full 4GB of VRAM, but it's still false advertising and shifty.
I don't buy the whole "miscommunication between the engineers and technical team" nVIDIA is trying to sell either.