Looks like the body hanging in the air keeps on sleeping and is thus not updated. Looks like you found a bug ;)
Two workarounds for you to try:
Set awake to true on a body before you remove it. That should wake up all adjecent bodies too.
If that does not work you could try setting sleepingallowed to false on all bodies. Not good for performance but should work in your case as long as you don't have to many objects on the screen at the samte time.
I'd consider both solutions a dirty hack though, so remember to remove them once uhm genbox has fixed this problem ;D