The volume toggling issue that has been plaguing the UK Galaxy Nexus over its first few days on the market was originally thought to be software-related. Many assumed that a simple OS tweak would take care of the problem, but that may not be the case after all. Through the testing you can see above, the volume rocker on the G-Nex is being toggled up and down even while in the bootloader, hence the scrolling between options on the screen.
From what we can tell, the tester has placed a call on his secondary phone, is then moving it up against the G-Nex which is causing the internal radio to freak out (official term there). When the radio is doing whatever the heck it is doing on the inside, it is also triggering the volume rocker to adjust all the way down, leading people to believe that this is a hardware problem rather than software.
Still no way to tell if this issue lives on the 4G LTE version until we get the phone in our hands.