Yeah, I suspected you were right about the 2nd unit being the replacement, so tried to verify whether that was the case. The DFF blog notes the Steorn email is worded such that the incorrect unit isn't part of the 2 'shipped' units.
"We have shipped two ocubes and have received reports back that the lithium ion battery in the devices is charging to somewhere in the region of 8V"
All part of the obfuscation maybe?