Hmm perhaps upon delivery (with R19.2?) it has been formatted as 12G. However if you flash according to the directions it will reduce to 8G. I think this is to reduce the flashing time over USB.
Yes Dustin is correct, we ship it with 12G but if you follow the custom Linux flashing instructions it gives you a smaller partition since it can take an extra hour or so of waiting for that extra 4GB of space during flashing. We are likely to simplify it so that both the shipped device and the custom instructions give you a single 12-13G partition.