Alright,
so i was playing offline against my self, testing some stuff out. I was casually roping along when suddenly i plunge into the water, because i ran out of ropes. I thought i must have messed up somehow, so i didn't bother about it. A short while later the same thing happens, and i decide to do some research.
I found that, if you detach the rope while swinging, then quickly tap space once to fire a short rope, and then fire again to attach the rope to something... it will count as being a new rope. in other words, you lose a rope.
I'm not quite sure whether or not this is the intended behaviour, so i thought i would post it here rather than in the bugs section.
P.s. i tested this in the dev. version and the same thing happens.