I was cruizin my 'liberated' pike around the forgotten shore and had to dismount when I was over water. While the vehicle floats above the surface when activated, it rested a foot or so deep in the water when I hopped off. And apparently, the fallen do not make water-resistant vehicles, since I could not get the thing to budge afterwards. I even had a Warlock mechanic come take a look and he couldn't do anything either. Eventually some of the Wolves came by and just wrecked it, anyways, but it was kind of disappointing