(probably only the simulator is affected)
I don't know if this is just OS specific or just that the Firefox OS simulator's backend cannot have a workaround for this.
Swiping starting from links drag the link somewhere instead of scrolling. Releasing the mouse does not 'lift the finger' and instead, follows the mouse as if 'the finger wasn't yet lifted'. A click somewhere else releases 'the finger'.
Browser: Firefox 18
Operating System: Fedora 17 Beefy Miracle
Simulator: Firefox OS Simulator 2.0pre5
Try clicking the Mouse Wheel button, as a temporary fix, while this is happening to fix the issue. Works for me ;P
This sounds like #114, which will be fixed by #166.