Stun Baton alt attack

Actually if I use alt attack once, it works fine, but if I press it two times to reposition my grapple hook it just fails. I press mouse2 button 2 times it does nothing and takes like 2 seconds to reposition it.

It's very annoying thing as a merc, since you can't save your life easily if you're falling, or using it to move faster on maps like t2_trip.

Maybe it's actually a feature (the delay on the grapple) but as I can see it's quite annoying.